# MCQ Questions for Class 6 Physics with Answers PDF Download | Chapterwise 6th Class Physics Objective Questions

MCQ Questions for Class 6 Physics with Answers can be extremely helpful for students who are willing to score good grades in academics. Solve the MCQ Quiz Questions of Class 6th Physics regularly to revise the syllabus as a part of your examination. In case if you need better assistance on the lesson you can go through our NCERT Solutions for Class 6 Science and clear your queries. You can test your knowledge using the Class 6 Physics Objective Questions PDF anytime and anywhere through the quick links available.

Students can crack the Class 6 Exams quite easily taking the help of the Chapterwise CBSE Physics MCQ Questions for Class 6 with Answers.

## CBSE Class 6 Physics Objective Questions (MCQ) Chapterwise

Utilize the Class 6th Physics MCQ Quiz Questions for All Chapters through the quick links present below. Choose the respective chapter you wish to prepare from the chapters mentioned below and resolve your doubts instantly.

### Class 6 Physics MCQ Questions Free PDF

Ace up your preparation using resources like NCERT Books for Class 6 Science, Sample Papers, Study Material. Subject experts have designed these MCQ Questions after extensive research keeping in mind the IQ Levels of different students. Revise the complete syllabus smartly taking the help of 6th Class Science Multiple Choice Question and Answers as we cover each and every topic in a simple and easy-to-understand language.

### Motion and Measurement of Distances MCQ Questions

1. Consider the following statements about motion
(i) Motion is observed when its position changes with time.
(ii) If an object moves very slowly then its movement can be observed easily.
(iii) Rectilinear motion takes place in a fixed direction.
Which of the above statements is/are correct?
(a) i and iii
(b) ii and iii
(c) i and ii
(d) i, ii, iii

Explanation:
The movement of an object is called motion and an object is said to be in motion when its position changes with time, if an object moves veiy fast then its movement can be observed easily but if an object moves veiy slowly, then it becomes difficult to observe its movement immediately. Motion in a straight line is called rectilinear motion. Example: the movement of a bullet fired from a gun is an example of rectilinear motion. Rectilinear motion takes place in a fixed direction. The motion which repeats itself after regular intervals of time is called periodic motion.

2. Rotation of the Earth is an example of
(a) Periodic motion
(b) Circular motion
(c) Both (a) and (b)
(d) None of these

Explanation:
The motion which repeats itself after regular intervals of time, is called periodic motion. Rotation of the Earth is a periodic motion because the Earth takes the same time( 24 hours) to rotate once on its axis. Having the shape of a circle is called circular path. When an object moves along a circular path a round path it is called circular motion. The Earth rotates around the sun in a circular path. Therefore, it is circular motion.

3. The communication satellite station is in an Orbit high above the Earth. Which of the following will not be exhibited by this communication satellite?
(i) Rotational motion
(ii) Periodic motion
(iii) Circular motion
(iv) Rectilinear motion
Which of the above statements is/are correct?
(a) i and ii
(b) ii and iii
(c) i and iv
(d) ii and iv

Explanation:
When an object turns (or spins) about a fixed axis, it is called rotational motion. If it does not revolve around any axis, then it is not an rotational motion. Motion in a straight line is called rectilinear motion or when an object moves along a straight line so is called rectilinear motion. The satellite does not move in a straight line so it is not rectilinear motion. When an object moves along a circular path, it is called circular motion. It moves around an object in space; it can be moon or earth. Therefore it is said to be in circular motion.

4. Which of the following precautions should be taken while using a scale?
(i) Scale should be placed parallel to the object.
(ii) The eye should not be placed vertical while reading.
(a) Only i
(b) Only ii
(c) Both i and ii
(d) Neither i nor ii

Explanation:
1. The scale should be placed parallel to the side of the object to be measured. It should also be in touch with the object being measured.
2. While reading the scale, the eye must be placed vertically above the scale mark being read.
3. If the scale has a damaged zero mark or broken left end, measure the length of an object starting from 1 cm mark of scale and then subtract 1 cm from the reading taken at the right end to get the actual length of object.

### Light, Shadows and Reflections MCQ Questions

1. Consider the following statements about a Luminous object :
(i) It is an object which does not give its own light.
(ii) They act as the sources of light.
Which of the above statements is/are correct?
(a) Only i
(b) Only ii
(c) Both i and .ii
(d) Neither i nor ii

Explanation:
An object with gives out its own light is called a luminous object. A Luminous object is a source of light. A luminous object can be seen because the light given out by it enters our eyes. An object which does not give out its own light is called a non-luminous object. A non-luminous object can be seen only when light coming from a luminous object falls on it. We can see the non-luminous object because it reflects light (received from a luminous object) into our eyes.

2. Consider the following statements about transparent objects :
(i) They allow all the light to pass through them.
(ii) Glass, polythene, air, water and butter paper are examples of transparent objects.
Which of the following statements is/are correct?
(a) Only i
(b) Only ii
(c) Both i and ii
(d) Neither i nor ii

Explanation:
The materials which allow all the light to pass through them are called transparent materials. Materials like glass, polythene, air, water and groundnut oil are transparent materials because we can see clearly through them. Those materials which allow only some light to pass through them are called translucent materials. Light passes only partially through translucent material. Butter paper is a translucent material because it does not allow to pass all the light through it. We cannot see clearly.

3. The intensity of Darkness of Shadows formed by different materials
(a) Translucent material > opaque material > transparent material
(b) Opaque material > transparent material > translucent material
(c) Opaque material > translucent material > transparent material
(d) Transparent material > opaque material > translucent material

Explanation:
Those materials which do not allow any light to pass through them are called opaque materials. An opaque object stops the light completely so an opaque object casts a Dark Shadow behind it. Those materials which allow only some light to pass through them are called translucent materials. A translucent object stops the light partially. So a translucent object casts a weak shadow (less Dark Shadow). A transparent object does not stop any light from passing through it, so a transparent material does not cast any Shadow behind it.

4. Consider the following statements :
(i) Source of light
(ii) Translucent object
(iii) Opaque object
(iv) A screen
The things required to observe a shadow are :
(a) i, ii and iv
(b) i, ii and iii
(c) i, ii, i and iv
(d) All the above

Explanation:
Shadows are formed when light is stopped by an object. Those materials which do not allow any light to pass through them are called opaque materials. An opaque object stops the light completely. Therefore, an opaque object is required. The shadow of an object can only be on a screen. An object forms shadow on the opposite side of the source of light. For the light to be stopped a source of light is also required.

5. The characteristics of a shadow are:
1. It is virtual and erect.
2. The image is of the same colour.
3. The shadow can be smaller, equal or bigger than the object.
4. It is erect.
Which of the above are correct?
(a) 1 and 3
(b) 2 and 4
(c) 3 and 4
(d) 2 and 4

Explanation:
1. The shadow is same side up as the object; therefore, it is an erect image.
2. The shadow can be obtained on the screen; therefore, it is real.
3. The shadow is always black irrespective of the colour of the object.
4. The shadow can be smaller than the object, equal to the object or bigger than the object.

6. Which of the following is not a characteristic of a virtual image formed in a plane mirror?
(a) Cannot be formed on a screen.
(b) It is inverted.
(c) It is the same size of the object.
(d) It is laterally inverted.

Explanation:
Characteristics of an image formed by the plane mirror are :
1. The image formed in a plane mirror is virtual.
2. The image formed in a plane mirror is the same distance behind the mirror as the object is in front of the mirror.
3. The image in a plane mirror is of the same size as the object.
4. The image formed in a plane mirror is erect.
5. The image is literally inverted.

7. Which of the following will produce diffuse reflection of light?
1. Plane mirror
2. Piece of paper
3. Still water in lake
4. Leather bag
(a) 1 and 2
(b) 2 and 3
(c) 1 and 4
(d) 2 and 4

Explanation:
Due to rough surfaces, most of the objects reflect light in all directions. This is called a regular reflection or diffuse reflection. For example, a white piece of paper has a rough surface so it reflects lights falling on it in all directions. Similar is the case with the leather bag.

### Electricity and Circuits MCQ Questions

1. Consider the following statements about a cell :
(i) It is also known as diy cell.
(ii) It produces an electricity of 2V.
Which of the above statements is /are correct?
(a) Only i
(b) Only ii
(c) Both i and ii
(d) Neither i nor ii

Explanation:
An electric cell is a device which produces a small amount of electricity. The electric cell produces electricity from the chemicals stored in it. We use an electric cell to get electricity that is safe for performing experiments. It is also known as a dry cell or a just cell. A single electric cell provides only 1.5 volt of electricity.

2. Which of the following types of energy can be converted easily into mechanical energy, sound energy, heat energy and light energy?
(a) Kinetic energy
(b) Potential energy
(c) Electric energy
(d) Magnetic energy

Explanation:
Electricity is a very clean form of energy. Elec-tricity is useful because it can be converted easily into various forms of energy such as heat energy, light energy, mechanical energy, and magnetism, etc. We use electricity to run many appliances in our day to day life which makes work easier.

3. When electricity passes through a bulb, it gives off :
1. Sound
2. Light
3. Electricity
4. Heat
Choose the correct option from the codes given below :
(a) 1 and 2
(b) 2 only
(c) 2 and 3
(d) 2 and 4

Explanation:
A bulb has two terminals marked positive and negative. When the two terminals of the a cell are connected to the two terminals of, the bulb by using wires, the electric current passes through the filament of the bulb and it starts glowing . When electricity from the cell passes through the filament of the bulb the filament gets heated too much. The filament becomes white hot and starts giving light.

4. The filament of an electric bulb is made up of a thin wire of:
(a) Copper
(b) Aluminium
(c) Tungsten
(d) Nichrome

Explanation:
When the electricity from the cell passes through the filament of the bulb, this element gets heated too much. The filament becomes white hot and starts giving light. So, we need a metal which has high melting point and get heated up fast. Therefore, we use tungsten.

5. The cells/ batteries which can be recharged Eire usually those in:
1. Electric clocks
2. Mobile phones
3. Cameras
4. TV remote
Choose the correct option:
(a) 1 and 2
(b) 2 and 3
(c) 3 and 4
(d) 1 and 4

Explanation:
An electric cell has a number of chemicals stored in it. The electric cell produces electriciiy from the chemicals stored in it. When £ill the chemicals in the electric cell are used up, the cell stops producing electricity. This electric cell has then to be thrown away and replaced with a new one. Ordinaiy electric cells cannot be recharged. Elec-tric cells or batteries used in cars, cameras Etnd mobile phones, etc. can be recharged again and again for many years.

### Fun with Magnets MCQ Questions

1. Consider the sraiements about magnetic, materials:
1. These are not attracted by magnet.
2. They can be converted into magnets.
Choose the correct option from the codes given below :
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
Those materials attracted by a magnet are called magnetic materials. Iron, steel, nickel and cobalt are attracted by a magnet, so iron, steel, nickel and cobalt are magnetic materials. All the objects made of iron and steel are also magnetic objects. They can be converted into magnets. Those materials which are not attracted by a magnet are called non-magnetic materials. Nonmagnetic materials cannot be converted into magnets.

2. The precaution in handling magnets is/are :
1. We should hit a magnet with a hammer.
2. We should store magnets properly.
Choose the correct option:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
The following precautions should be taken while handling magnets:
1. We should never heat a magnet over the burner.
2. We should never hit a magnet with a hammer.
3. We should never drop a magnet on the floor.
4. We should store magnets properly when not in use.

3. Electromagnet is a:
(a) Bar magnet
(b) Damaged magnet
(c) Temporary magnet
(d) Permanent magnet

Explanation:
Magnets made by using electricity are called elec-tromagnets. They are very useful because their magnetism can be switched on or off as desired. If the electric current is switched on through its coil the electromagnet gets its magnetism and when an electric current through its coil is switched off, the electromagnet loses all its magnetism.

4. A magnet is made of:
1. Steel
2. Copper
3. Aluminium
4. Iron
Choose the correct option:
(a) 1 or 2
(b) 1 or 4
(c) 2 or 3
(d) 3 or 4

Explanation:
Magnets are made up of magnetic materials. Magnetic materials are those which are attracted by a magnet. Iron, steel, nickel and cobalt are at-tracted by a magnet so, are magnetic materials.

### Heat MCQ Questions

1. Which of the following statements is/are correct about heat?
1. It causes the sensation of hotness and cold ness.
2. When a body is heated, its energy decreases.
3. S.I. unit is Joule.
Choose the correct option from the codes given below :
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1,2 and 3

Explanation:
Heat is a form of energy which causes the sensa-tion of hotness and coldness. When a body is heated, its energy increases and when it is cooled, its energy decreases. Heat is measured by change in the degree of hotness and coldness it produces in material bodies. The non S.I. units are calorie and kilocalorie. The S.I unit is Joule.

2. Which of the following statements is/are correct about laboratory thermometer?
1. Size is larger than clinical thermometer.
2. Range is 35-42 degree Celsius.
3. It is cylindrical in shape.
4. It has straight capillary.
Choose the correct option from the codes given below:
(a) 1, 2, 3 and 4
(b) 1, 2 and 3
(c) 1, 3 and 4
(d) 2, 3 and 4

Explanation:
A laboratory thermometer is much larger than clinical thermometer. Its temperature range is 0-100 degree Celsius. Its bulb remains in contact with the substance or body. The design of body is simple and cylindrical. It has a straight capillary and thermometric liquid is mercury.

3. Which of the following is/are correctly matched?
1. Conduction _________ objects should be in direct con-tact.
2. Convention _________ heat is carried by actual movement of hot particles.
Choose the correct option from the codes given below :
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1,2 and 3

Explanation:
Heat conduction from an object to another takes place only under the following two conditions:
(a) The two objects should be in direct contact.
(b) The two objects should be at different tem-perature.
When liquids and gases are heated, the heat is carried from one part to another by the actual movement of the hot particles. This movement of particles due to the temperature difference between different parts of the same substance is called convection.
All hot substances/objects whether solids, liquids or gases, transfer heat by radiation. Radiation needs no medium. Transfer of heat by radiation can occur even in vacuum.

4. Which of the following statements is/are correct for Celsius scale?
1. It was designed by Anders Celsius.
2. It is a metric scale of temperature.
3. It is called laboratory thermometer.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The Celsius scale temperature was designed by Anders Celsius (1701-1744). This scale tempera-ture is described in degree Celsius. It is a metric scale of temperature. The lower fixed point of the Celsius scale is taken as zero degree Celsius and the upper fixed point of this scale is taken as 100 degree Celsius. It is also called Clinical Ther-mometer.

### Motion and Time MCQ Questions

1. Which of the following is/are correct for simple pendulum?
1. Huygens suggested that a pendulum can be used to regulate clocks
2. Rest position is also called mean position.
3. The maximum displacement from the mean position is called amplitude of the pendulum.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1,2 and 3

Explanation:
Galileo in 1583 suggested that a pendulum can be used to regulate clocks. In 1658 , Huygens actually used the pendulum to regulate the motion in clocks. A simple pendulum consists of a small metallic ball ( called bob ) suspended by a light string (thread ) from a frictionless , rigid support rest position is also called mean position. The maximum displacement from the mean position is called amplitude of the pendulum.

2. Which of the following is/are correct for uniform motion?
1. A body moving with constant speed.
2. The distance travelled is inversely propor-tional to time.
Choose the correct option from the codes given . below:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
A body is said to be in uniform motion when it covers equal distances in equal intervals of time. A body with a constant speed is said to be in uniform motion. For uniform motion, the dis-tance travelled is directly proportional to time.

3. Which of the following is not a use of graph?
(a) It can represent a large amount of data in compact form.
(b) It makes the comparison of data difficult.
(c) It shows geometrical dependence.
(d) It can be used to obtain value of one quantity.

Explanation:
Graphs are useful in the following ways:
1. A graphical plot can represent a large mount of data in a compact form.
2. A graphical plot shows geometrical depen-dence of one quantity over the other.
3. A graphical plot makes the comparison of dif-ferent sets of data easier.
4. A graphical plot can be used to obtain value of one quantity for a specified value of the other.

### Electric Current and its effects MCQ Questions

1. Which of the following is not correctly matched?
(a) Electric cell _________ a set of two short vertical lines.
(b) Connecting wires _________ straight lines
(c) Wires connected together _________ circle with a dot inside.
(d) Switch off _________ two points.

Explanation:
An electrical cell is represented by two vertical lines. One of them is slightly shorter and thicker than the other. The longer line represents positive terminal and the shorter line represents the negative terminal of the cell. An electric bulb is represented by a circle with a curved wire inside it. Connecting wires are represented by straight lines. The connection between two wires is rep-resented by a dot at the connecting point. Each switch have two points. When the two points are not connected, the circuit remains open. When the two points in the switch are connected, it gets closed.

2. Which of the following is/are correct for electrical circuit?
1. It is a continuous path.
2. It can be open or closed.
3. When electrical contact is broken, it is called a closed circuit.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The continuous path of flow of electricity through various electrical components connected to a source of electricity is called an electrical circuit. An electrical circuit can be closed or open. The circuit in which electric current flows from positive terminal of a battery to the negative ter-minal through all the components in the circuit is called a closed circuit. The circuit in which electrical contact at any point in the circuit is broken is called an open circuit,

3. Which of the following is/are correctly matched?
1. Heating effect of electric current _________ production of heat in the resistor
2. Magnetic effect of electric current _________ Hans Christian Oersted
3. Chemical Effect of electric current _________ electric fuse
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
When electric current flows through a resistor, such as, heating coil of nichrome wire, it gets heated up. The generation (production) of heat in a resistor (or conductor) when electricity passes through it is called heating effect of current. The heat produced in a resistor when electricity passes through it is called heating effect of current. The heat produced in a resistor when current is passed through it depends on the following factors :
• Current passed through the resistor.
• Time for which the current is passed.
• Nature of the material.
Electric fuse is the application of heating effect of current. A Danish scientist Hans Christian Oersted in 1819 discovered that when an electric current (DC) is passed through any conductor, a magnetic field is produced around it.

4. Which of the following is/are correct for electric bell?
1. It is based on heating effect of electric current.
2. A U-shaped or horseshoe-shaped electromag-net is used.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
The electric bell is based on the magnetic effect of electric current. The main components of an electric bell are :
• Electromagnet: A u-shaped (or horseshoe-shaped) electromagnet.
• Armature: A soft iron armature fixed to the spring strip facing the two poles of the elec-tromagnet.
• Strip string: A metallic strip, slightly bent and fixed to the armature.
• Contact Screw: A contact make-break screw.
• Hammer: A hammer made of steel and fixed to the armature.
• Switch: A push button type switch.
• Gong: A circular hollow disc made of brass.

5. Which of the following is/are correctly matched?
1. Open circuit _________ no flow of current
2. Copper _________ good conductor
Choose the correct option from the codes given below :
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The circuit in which electric current flows from positive terminal of a battery to the negative ter-minal through all the components in the circuit is called a closed circuit. The circuit in which elec-trical contact at any point in the circuit is broken is called an open circuit. Copper is a good conductor as metal are good conductors of heat and electricity. Electric fuse, made of nichrome wire is the application of heating effect of current.

### Light MCQ Questions

1. Which of the following is/are correctly matched?
1. Ray of light _____straight line
2. Beam of light ______ bundle of rays of light
3. Divergent ______ rays coming closer
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
A very narrow path of light described by a straight line drawn in direction of propagation of light is called a ray of light. A broader bundle of light rays is called a beam of light. A beam of light consisting of parallel rays of light is called a parallel beam of light. A beam of light consisting of rays diverging from a point source is called a divergent ray of light. A beam of light consisting of rays coming closer to each other, ultimately to meet at a point, is called a convergent beam of light.

2. Which of the following is/are correctly matched?
1. Plane mirror ______ highly polished surface.
2. Curved mirror ______ reflecting surface is curved.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
A smooth, highly polished reflecting surface is called a mirror. There are two types of mirrors: A highly polished plane surface is called a plane mirror. In curved mirrors, the reflecting surface is curved. The curved mirrors are called spherical mirrors or parabolic mirrors depending upon their curvature. A plane mirror can be obtained by silvering one side of a glass sheet.

3. Which of the following is/are correct for reflection?
1. The ray of light which falls on the smooth polished surface is called the incident ray.
2. The ray of light which gets bounced off is reflected ray.
3. The angle of incidence is not equal to the angle of reflection.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
When a ray of light falls on a mirror, it gets re-flected. The ray of light which falls on the smooth polished surface is called the incident ray of light and the ray of light which gets bounced off or reflected from the smooth polished surface is called the reflected ray of light. The angle between the incident ray and the normal ray at the point of incidence is called angle of incidence. The angle between the reflected ray and the normal ray is called the reflect ray. The angle of incidence is equal to the angle of reflection.

4. Which of the following statements is/ are correct for a virtual image?
1. The rays of light actually meet at the point.
2. The image cannot be obtained on the screen Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
When the ray of light after suffering reflection from a mirror actually meets at a point, the im-age formed can be obtained and seen on a screen.
The image which can be obtained on the screen is called a real image. When the rays of the light after suffering reflection from the mirror appear to meet at a point , the image formed cannot be obtained on a screen and can only be seen into the mirror. The image which can only be seen into a mirror but cannot be obtained on a screen is called a virtual image.

5. Which of the following is/are correct for a convex lens?
1. It is thicker in the middle.
2. It always forms virtual and erect image.
3. It is a converging lens.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 & 3
(c) 1 & 3
(d) 1,2 & 3

Explanation:
Convex lens is thicker in the middle and thinner at the edges. It is a converging lens. It forms real and inverted image for the all the distances except when the object is placed very close to the lens. Concave lens is a diverging lens and always forms virtual , erect and smaller images, what-ever be the position

### Sound MCQ Questions

1. Which of the following is/are correctly matched?
The movement of a body from one extreme position to the other and back is called an oscillation. The
1. Oscillation _________ movement of a body.
2. Amplitude _________ maximum displacement from mean position.
3. frequency _________ time period.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
maximum displacement of a body from its mean position is called the amplitude of oscillation. The number of oscillations made by an oscillating body in one second is called the frequency of oscillation. It is the reciprocal of time period.

2. Which of the following is/are correctly matched?
1. Sonic sound _________ 20-20000 Hz
2. Ultrasonic sound _________ greater than 2000 Hz
3. Infrasonic sound _________ less than 20 Hz
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The human ear can hear the sounds having fre-quencies between 20Hz to 20000Hz. This is called the audible range. The sound in the audible range is called sonic sound. The sound of frequencies greater than 20000 Hz is called ultrasonic sound. The sound of frequencies lower than 20 Hz is called subsonic or infrasonic sound.

3. Which of the following difference between noise and musical sound is correct?

 Noise Musical sound 1. Irregular waveform regular waveform 2. High Frequency low frequency 3. Irregular and nonperiodic vibration regular and periodic vibration

Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The characteristics of noise are:
• Irregular waveform
• Low frequency
• Irregular and non-periodic vibration
• Discordant effect on human ear The characteristics of musical sound are:
• Regular waveform
• High frequency
• Regular and periodic vibration
• Pleasant and comfortable effect on human ear and mind of a person

4. Which of the following is/are effects of noise pollution?
1. Hearing Loss
2. Fatigue
3. Low blood pressure
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
Loud and harsh sound is called noise. The dis-turbance caused by an undesirable loud sound of different kinds is called noise pollution. The harmful effects of the noise pollution are :
1. Hearing loss
2. Fatigue due to lack of sleep
3. High blood pressure
4. Anxiety

### Chemical effects of Electric Current MCQ Questions

1. Which of the following is/ are correct for electrolytic solution?
1. Electrolyte conducts electricity when dissolved in water.
2. Sodium chloride, sugar solution, sulphuric acid are electrolytic solution.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
A substance which gives ions when melted or dis-solved in water is called an electrolyte. It may be defined as a substance which conducts electricity when dissolved in water or when melted. Sodium chloride, sulphuric acid are electrolytes as they dissociate into ions but sugar solution doesn’t dissociate into ions when melted or dissolved in water so it is a non-electrolyte.

2. Which of the following is/are correct for conductors?
1. They allow flow of electricity.
2. Solution of weak electrolyte are good conductors.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
Material which allows electricity to flow through them are called conductors. Silver, copper, iron are conductors. Solutions of strong electrolyte and molten electrolyte are good conductors of electricity. The solutions of weak electrolyte are poor conductors.

3. Which of the following is the correct order of the conductivity
(a) Alloys > insulators > semiconductors
(b) Insulators > alloys semiconductors
(c) Alloys>semiconductors>insulators
(d) Semiconductor > alloys > insulators

Explanation:
Various substances are listed below in the order of decreasing conductivity :
• Metal alloys
• Molten electrolytes
• Electrolytic solutions
• Semiconductors -poor conductors
• Insulators- non-conductors

4. Which of the following is/are the correct for LED?
1. It emits light only when weak current flows through it.
2. It is an electronic device.
3. The longer lead is positive.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
An LED is an electronic device. Its starts emitting light even when very weak current flows through it. It has two leads. The longer one is positive and the smaller one is negative. LEDs are available in different colours.

5. Which of the following is/are correctly matched?
1. Electrolyte _________ conductor
2. Cation _________ positive ion
3. Bakelite _________ poor conductor
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
Electrolyte conducts electricity when dissolved in water or in molten state, therefore, it is a good conductor. An electrolyte when dissolved in water produces ions. These ions are free to move throughout the solution. The positively charged ions are called Cation. Bakelite is a polymer which is used to make electrical switches, it is a poor conductor.

### Force and Pressure MCQ Questions

1. Which of the following is/are true about force?
1. It is a push or pull.
2. It is denoted F.
3. It SI unit is newton.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 & 3
(c) 1 & 3
(d) 1,2 & 3

Explanation:
A push or pull acting on a body which tends to change its state of rest or of motion is called force. Force is usually denoted by the letter F the direction in which the body is pushed or pulled is called direction of force. The standard unit of force is called newton, denoted by the letter N.

2. Which of the following is/are correct for contact forces?
1. There should be a contact between two objects.
2. Magnetic force is an example.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
For an object to be pushed or pulled , there should be a contact between two objects. The contact forces interact physically to see the force come into play.
Examples are :- muscular force and frictional force. Magnetic force is an example of non contact force.

3. Which of the following is/are correct for electrostatic force?
1. It is between two charged bodies.
2. Electrostatic charge can be created.
Choose the correct option from the codes given below :
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
The force between two charged bodies, one charged and other uncharged due to which they repel and attract each other is called electrostatic force. Electrostatic force between two charged bodies varies directly to the product of electrical charges and inversely to the square of the dis-tance .The electrostatic charge as any body can be transferred but not created or destroyed.

4. Which of the following is not the effect of force?
(a) It changes the state of motion or rest.
(b) Change in direction of motion of stationary object.
(c) Change in shape and size.
(d) Change the speed of the moving object.

Explanation:
Force acting on a body may cause the following effects on it :
1. A force acting on a body changes its state of motion or rest.
2. A force can change the direction of motion of a moving object.
3. A force can change the shape and size of an object.
4. A force can stop a moving object.
5. A force can change the speed of the moving object.

5. Which of the following statements is/are correct for pressure exerted by liquids?
1. It depends upon depth.
2. It depends upon the shape and size of the container.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
A liquid contained in a vessel exerts pressure on its wall and bottom
1. Pressure at a point in a liquid depends upon its depth.
2. Pressure of a liquid is the same in all the directions at the same depth.
3. Pressure of a liquid doesn’t depend upon the shape and the size of the container.
4. Pressure applied to the liquid is transmitted equally in all the directions.

6. Which of the following statements is/are correct for pressure exerted by air?
1. It is called atmospheric pressure.
2. It is measured by aneroid barometer.
3. It increases with altitude.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 & 3
(c) 1 & 3
(d) 1,2 & 3

Explanation:
The pressure exerted by air oil the earth is called atmospheric pressure at that point. Simple ba-rometer and aneroid barometer are used to mea-sure it. It decreases with altitude, that is, it de-creases as we go up in the atmosphere.

### Friction MCQ Questions

1. Which of the following statements is/are correct for friction?
1. It acts along two surfaces in contact.
2. It opposes motion.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
According to the Newton’s first law of motion a body continues to be in its state of rest or of uniform motion in a straight line unless an external force acts on it. But every object stops after some motion with a force of friction. The force acting along the two surfaces in contact which opposes motion of one body over other is called the force of friction.

2. On which of the following factors does the force of friction depend upon :
1. Weight of the body
2. Nature of the surface
3. Area of the surfaces in contact
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 & 3
(c) 1 & 3
(d) 1,2 & 3

Explanation:
The force which opposes the motion of one body over the other is called the force of friction.
1. On a horizontal surface, the force of friction is directly proportional to the weight of the body which moves.
2. The force of friction depends upon the nature of surface in contact.
3. The force of friction doesn’t depend upon the area of the surfaces in contact.

3. Which of the following is/are correctly matched ?
1. Static friction _________ self-adjusting force
2. Sliding friction _________ less than limiting friction
3. Rolling friction _________ greater than sliding friction
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 & 3
(c) 1 & 3
(d) 1,2 & 3

Explanation:
Friction is selfadjusting force. When the applied force is gradually increased the force of friction also increases at the same rate and body remains stationary. This force of friction is called force of static friction. The force of friction between the two surfaces in contact with one of them just over the other is called sliding friction. It is less than the limiting static friction. The force of friction between the two surfaces in contact with one of them rolling over the other is called the rolling friction. It is much smaller than sliding friction.

4. Which of the following is/are ways to increase friction?
1. Making the surfaces corrugated
2. Rubbing the hands with soap
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

### Gravitation MCQ Questions

1. Which of the following statements is/are correct for centripetal force?
1. It keeps the body moving along the circular path.
2. The object flies off along a straight line. Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
The change in direction involves change in ve-locity or acceleration. The force that causes this acceleration and keeps the body moving along the circular path is acting towards the centre. This force is called the centripetal (meaning ‘centreseeking’) force. In the absence of this force, the object flies off along a straight line. This straight line will be a tangent to the circular path.

2. Which of the following statements is/are correct for gravitational force?
1. All objects in the universe attract each other.
2. The force between two objects is directly pro-portional to the square of the distance between them.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
All objects in the universe attract each other. This force of attraction between objects is called the gravitational force. According to the universal law of gravitation, the force between two objects is directly proportional to the product of their masses. The force between two objects is inversely proportional to the square of the distance between them.

3. Which of the following statements is/are correct for Kepler’s laws?
1. The orbit of a planet is an circle.
2. The cube of the mean distance of a planet from the Sun is proportional to the square of its orbital period.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
Johannes Kepler derived three laws, which gov-ern the motion of planets. These are called Kepler’s laws. These are:
• The orbit of a planet is an ellipse with the Sun at one of the two foci.
• The line joining the planet and the Sun sweep equal areas in equal intervals of time.
• The cube of the mean distance of a planet from the Sim is proportional to the square of its orbital period T. Or, r 3/T2 = constant.

4. Which of the following is/are the applications of gravitational force?
1. The force that binds us to the earth;
2. The motion of the moon around the earth;
3. The motion of planets around the Sun Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The universal law of gravitation successfully ex-plains several phenomena which are believed to be unconnected:
(i) the force that binds us to the earth;
(ii) the motion of the moon around the earth;
(iii) the motion of planets around the Sun; and
(iv) the tides due to the moon and the Sun.

5. Which of the following is/are correct for thrust and pressure?
1. The force acting on an object perpendicular to the surface is called thrust.
2. The thrust on unit area is called pressure.
3. SI unit of pressure is called pascal.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The force acting on an object perpendicular to the surface is called thrust. When you stand on loose sand, the force, that is, the weight of your body is acting on an area equal to area of your feet. When you lie down, the same force acts on an area equal to the contact area of your whole body, which is larger than the area of your feet. Thus, the effects of forces of the same magnitude on different areas are different. In the above cases, thrust is the same. But effects are different. Therefore the effect of thrust depends on the area on which it acts. The effect of thrust on sand is larger while standing than while lying. The thrust on unit area is called pressure. Thus, thrust= Pressure/area. The SI unit of pressure is N/m2 or N m-2 . In honour of scientist Blaise Pascal, the SI unit of pressure is called pascal, denoted as Pa.

### Work, Power and Energy MCQ Questions

1. Which of the following is/are conditions for work done?
1. A force should act on an object.
2. The object must cover distance.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
Two conditions need to be satisfied for work to be done:
(i) a force should act on an object, and
(ii) the object must be displaced. If anyone of the above conditions does not exist, work is not done.

2. Which of the following is/are correct for energy?
1. The energy possessed by an object is measured in terms of its capacity of doing work.
2. Its S.I. unit is kJ.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
The energy possessed by an object is measured in terms of its capacity of doing work. The unit of energy is, therefore, the same as that of work, that is, joule (J). 1 J is the energy required to do 1 joule of work. Sometimes a larger unit of energy called kilo joule (kJ) is used. 1 kJ equals 1000 J.

3. Which of the following is/are correctly matched?
1. Kinetic energy _________ motion
2. Potential energy _________ position
3. Mechanical energy _________ kinetic energy + heat energy
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The various forms include mechanical energy (potential energy + kinetic energy), heat energy, chemical energy, electrical energy and light energy. The kinetic energy of a body moving with a certain velocity is equal to the work done on it to make it acquire that velocity. The energy gets stored due to the work done on the object. The energy transferred to an object is stored as potential energy if it is not used to cause a change in the velocity or speed of the object. The potential energy possessed by the object is the energy present in it by virtue of its position or configuration.

4. Which of the following is/are correct for law of conservation of energy?
1. Energy can be converted from one form to another.
2. It can be created.
Choose the correct option from the codes given below :
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
Whenever energy gets transformed, the total energy remains unchanged. This is the law of conservation of energy. According to this law, energy can only be converted from one form to another; it can neither be created nor destroyed. The total energy before and after the transformation remains the same. The law of conservation of energy is valid in all situations and for all kinds of transformations.

5. Which of the following is/are correct for power?
1. Power measures the speed of motion.
2. It was given by James Watt.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
Power measures the speed of work done, that is, how fast or slow work is done. Power is defined as the rate of doing work or the rate of transfer of energy. The unit of power is watt [in honour of James Watt (1736 – 1819)] having the symbol W. 1 watt is the power of an agent, which does work at the rate of 1 joule per second. We can also say that power is 1 W when the rate of consumption of energy is 1 J/s.

### Sound MCQ Questions

1. Which of the following is/are correct for sound?
1. It is a form of energy.
2. It does not need a medium to travel.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
Sound is a form of energy which produces a sensation of hearing in our ears. There are also other forms of energy like mechanical energy, light energy, etc. Sound is produced by vibrating objects. The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. Sound moves through a medium from the point of generation to the listener. When an object vibrates, it sets the particles of the medium around it vibrating. The particles do not travel all the way from the vibrating object to the ear. Sound is a mechanical wave and needs a material medium like air, water, steel, etc. for its propagation. It cannot travel through vacuum.

2. Which of the following is/are correct for waves?
1. It is a disturbance in the medium.
2. Sound waves are mechanical waves.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
A wave is a disturbance that moves through a medium when the particles of the medium set neighbouring particles into motion. They in turn produce similar motion in others. The particles of the medium do not move forward themselves, but the disturbance is carried forward. This is what happens during propagation of sound in a medium, hence sound can be visualised as a wave. Sound waves Eire characterised by the motion of particles in the medium and Eire csilled mechanical waves.

3. Which of the following is/are correctly matched?
1. Longitudinal wave _________ direction of particles parallel to direction of propagation.
2. Transverse wave _________ direction of particles perpendicular to direction of propagation.
3. Compression _________ density is low.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1,2 and 3

Explanation:
In longitudinEil waves, the individual particles of the medium move in a direction parallel to the direction of propagation of the disturbance. The particles do not move from one place to another but they simply oscillate back and forth about their position of rest. In a transverse wave par-ticles do not oscillate along the direction of wave propagation but oscillate up Eind down about their mean position as the wave travels. Thus, a transverse wave is the one in which the individual particles of the medium move about their mean positions in a direction perpendicular to the di-rection of wave propagation. Compressions are the regions where particles are crowded together and represented by the upper portion of the curve. The peak represents the region of maximum com-pression. Thus, compressions are regions where density as well as pressure is high. Rctrefactions are the regions of low pressure where particles are spread apsirt and are represented by the val-ley, that is, the lower portion of the curve.

4. Which of the following is/are true for speed of sound?
1. The speed of sound in a medium is inversely proportional to the temperature of the medium.
2. The speed of sound decreases when we go from solid to gaseous state.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 & 2
(d) Neither 1 nor 2

Explanation:
The speed of sound in a medium depends on the temperature of the medium. The speed of sound decreases when we go from solid to gaseous state. In any medium, as we increase the temperature, the speed of sound increases.

5. Which of the following is/are uses of multiple reflection of sound?
1. Megaphones or loudhailers, horns
2. Stethoscope
3. Optical Fibre
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1,2 and 3

Explanation:
The repeated reflection that results in this per-sistence of sound is called reverberation. Mega-phones or loudhailers, horns, musical instruments such as trumpets and shehanals, are all designed to send sound in a particular direction without spreading it in all directions. Stethoscope is a medical instrument used for listening to sounds produced within the body, mainly in the heart or lungs. In stethoscopes the sound of the patient’s heEirtbeat reaches the doctor’s ears by multiple reflection of sound.

6. Which of the following is/are true for ultrasound?
1. It is a low frequency sound.
2. It is used to detect flaws in metal block.
3. It is used to get image of internal organs. Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1,2 and 3

Explanation:
Ultrasounds are high frequency waves. Ultra-sounds are able to travel along well defined paths even in the presence of obstacles. Ultrasounds are used extensively in industries and for medical purposes. Ultrasounds can be used to detect cracks and flaws in metal blocks. Metallic components are generally used in construction of big structures like buildings, bridges, machines and also scientific equipment. Ultrasonic waves are made to reflect from various parts of the heart and form the image of the heart. This technique is called ‘echocardiography. Ultrasound scanner is an instrument which uses ultrasonic waves for getting images of internal organs of the human body.

### Motion MCQ Questions

1. Which of the following is/are correct for displacement?
1. It is the shortest distance between initial and final point.
2. Its S.I unit is metre.
3. It is a scalar quantity.
Choose the correct option from the codes given below:
(a) 1 and 2 (b) 2 and 3
(c) 1 and 3 (d) 1, 2 and 3

Explanation:
Displacement is the shortest distance between initial and final point. Its S.I. unit is metre. The numerical value of a physical quantity is its mag-nitude. The magnitude of the displacement for a course of motion may be zero. Displacement has direction also. Therefore, it is a vector quantity.

2. Which of the following is/are correctly matched?
1. Speed ______ scalar
2. Velocity ______ vector
3. Acceleration ______ vector
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
Speed is distance covered per unit time. It is a scalar quantity. Velocity is the speed of an object moving in a definite direction. The velocity of an object can be uniform or variable. It can be changed by changing the object’s speed, direction of motion or both. Therefore, it is a vector quantity. Acceleration is change in velocity per unit time. Its has both magnitude and direction. Therefore, it is a scalar quantity.

3. Which of the following is/are correct for distance-time graphs?
1. Time is taken along the y-axis.
2. It determines the speed of an object.
3. It can also be plotted for accelerated motion. Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The change in the position of an object with time can be represented on the distance-time graph adopting a convenient scale of choice. In this graph, time is taken along the x-axis and distance is taken along the y-axis. Distance-time graphs can be employed under various conditions where objects move with uniform speed, non-uniform speed, remain at rest, etc. It can be used to deter-mine the speed of an object. We can also plot the distance-time graph for accelerated motion.

### Light-Reflection and Refraction MCQ Questions

1. Consider the following statements about refraction of light :
1. The incident ray, refracted ray and the normal ray lie in the same plane
2. The angle of incidence is equal to angle of refraction.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
The laws of refraction of light are:
• The incident ray, the refracted ray and the normal ray to the interface of two transparent media at the point of incidence, all lie in the same plane.
• The ratio of sine of angle of incidence to the sine of angle of refraction is constant, for the light of a given colour and for the given pair of media. This law is also known as Snell’s law of refraction. (This is true for angle 0 < i < 90) If i is the angle of incidence and r is the angle of refraction, then, sin i/ sin r = constant

2. Which of the following are correctly matched for the concave mirror?

 Object Image Between P and F at infinity At C at C Beyond C between F and C At infinity at focus

Choose the correct option from the codes given below:
(a) 1, 3, 4
(b) 2, 3, 4
(c) 1, 2, 3
(d) 1, 2, 3, 4

Explanation: 3. As light travels from a rarer to a denser medium it will have
(a) increased velocity
(b) decreased velocity
(c) decreased wavelength
(d) Both (b) and (c)

Explanation:
Refraction of light occurs because of change in velocity or speed of light in different media. When ray of light travels from rarer to denser medium, it moves towards the normal. When it travels from denser to rarer medium, it moves away from the normal. When light ray travels from rarer to denser medium, its velocity and wavelength both decrease.

4. The correct order of refractive index of various materials is :
a. Diamond > Ice > Alcohol > Rock salt
b. Ice> Diamond > Rock salt > Alcohol
c. Diamond > Rock salt > Alcohol >Ice
d. Rock salt > Alcohol > Ice > Diamond

Explanation:
• Air: 1.0003
• Ice: 1.31
• Water: 1.33
• Alcohol: 1.36
• Kerosene: 1.44
• Fused quartz: 1.46
• Turpentine oil: 1.47
• Benzene: 1.50
• Crown glass: 1.52
• Rock salt: 1.54
• Carbon disulphide: 1.63
• Ruby: 1.71
• Sapphire: 1.77
• Diamond: 2.42

### Human Eye and the Colourful World MCQ Questions

1. Which of the following is/are correctly matched?
1. Cornea _________ transparent bulge on the front part.
2. Pupil _________ present behind cornea.
3. Iris ______ controls the size of the pupil.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1,2 and 3

Explanation:
The human eye is like a camera. Its lens system forms an image on a light-sensitive screen called the retina. Light enters the eye through a thin membrane called the cornea. It forms the trans-parent bulge on the front surface of the eyeball. The eyeball is approximately spherical in shape with a diameter of about 2.3 cm. Most of the refraction for the light rays entering the eye occurs at the outer surface of the cornea. The crystalline lens merely provides the finer adjustment of focal length required to focus objects at different distances on the retina. There is a structure called iris behind the cornea. Iris is a dark muscular diaphragm that controls the size of the pupil. The pupil regulates and controls the amount of light entering the eye.

2. Consider the following statements about myopia:
1. It is called far-sightedness.
2. It is due to excessive curvature of lens.
3. It is corrected using concave lens.
Choose the correct option from the codes given below:
(a) 2 and 3
(b) 1 and 3
(c) 1 and 2
(d) 1, 2 and 3

Explanation:
Myopia is also known as near-sightedness. A person with myopia can see nearby objects clearly but cannot see distant objects distinctly. A person with this defect has the far point nearer than infinity. This defect may arise due to (i) excessive curvature of the eye lens, or (ii) elongation of the eyeball. This defect can be corrected by using a concave lens of suitable power.

3. Consider the following statements about dispersion by glass prism :
1. Splitting of light into its component colours is called dispersion.
2. Issac Newton was the first to observe disper-sion.
Choose the correct option from the codes given I below:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
The prism splits the incident white light into a ’ band of colours. The various colours seen are
Violet, Indigo, Blue, Green, Yellow, Orange and Red. The acronym VIBGYOR will help us to re- i member the sequence of colours. The band of the
coloured components of a light beam is called its spectrum. The splitting of light into its compo- I nent colours is called dispersion. Isaac Newton was the first to use a glass prism to obtain the spectrum of sunlight. He tried to split the colours of the spectrum of white light further by using
another similar prism. However, he could not get ; any more colours. He then placed a second identical prism in an inverted position with respect to the first prism.

4. Which of the following is/are effects of atmospheric refraction?
1. Twinkling of stars.
2. Tyndall effect
3. Advance sunrise and delayed sunset 1 Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
The twinkling of a star is due to atmospheric refraction of starlight. The starlight, on entering the earth’s atmosphere, undergoes refraction continuously before it reaches the earth. The atmospheric refraction occurs in a medium of gradually changing refractive index. Since the atmosphere bends starlight towards the normal, the apparent position of the star is slightly different from its actual position. The star appears slightly higher (above) than its actual position when viewed near the horizon. The Sun is visible to us about 2 minutes before the actual sunrise, and about 2 minutes after the actual sunset because of atmospheric refraction. By actual sunrise, we mean the actual crossing of the horizon by the Sun. The earth’s atmosphere is a heterogeneous mixture of minute particles. These particles include smoke, tiny water droplets, suspended particles of dust and molecules of air. When a beam of light strikes such fine particles, the path of the beam becomes visible. The light reaches us, after being reflected diffusely by these particles. The phenomenon of scattering of light by the colloidal particles gives rise to Tyndall effect.

5. Consider the following statements about electric circuit :
1. It is the rate of flow of electric charges.
2. Its S.I unit is Ampere.
3. It is measured using Ammeter.
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

Explanation:
Electric current is expressed by the amount of charge flowing through a particular area in unit time. In other words, it is the rate of flow of elec-tric charges. In circuits using metallic wires, elec-trons constitute the flow of charges. Electric cur-rent is considered to be the flow of positive charges and the direction of flow of positive charges is taken to be the direction of electric current. The electric current is expressed by a unit called am-pere (A), named after the French scientist, Andre- Marie Ampere (1775-1836). An instrument called ammeter measures electric current in a circuit. It is always connected in series in a circuit through which the current is to be measured.

6. Which of the following is/are correctly matched?
1. Charge ______ Coulomb
2. Potential Difference ______ Volts
3. Resistivity ______ Ohm metre
4. Electrical energy ______ Watt Hour
Choose the correct option from the codes given below:
(a) 1, 2 and 4
(b) 1,2 and 3
(c) 1,3 and 4
(d) 1,2, 3 and 4

Explanation:
If a net charge Q, flows across any cross-section of a conductor in time t, then the current I, through the cross-section is I =Q /t. The SI unit of electric charge is coulomb (C), which is equivalent to the charge contained in nearly 6×10 raise to power 18 electrons. The electric potential difference between two points in an electric circuit carrying some current as the work done to move a unit charge from one point to the other. Tire SI unit of electric potential difference is volt (V), named after Alessandro Volta (1745-1827), an Italian physicist. Resistivity is a characteristic property of the material. The SI unit of resistivity is £1 m. Electrical energy is the product of power and time, the unit of electric energy is, therefore, watt hour (W h). One watt hour is the energy consumed when 1 watt of power is used for 1 hour.

7. Consider the following statements about relationship between potential difference and current :
1. It was given by George Simon Ohm.
2. The potential difference is directly proportional to the current.
3. Its temperature remains the same or not.
Choose the correct option from the codes given below:
(a) 1 and 3
(b) 1 and 2
(c) 2 and 3
(d) 1, 2 and 3

Explanation:
In 1827, a German physicist Georg Simon Ohm (1787-1854) found out the relationship between the current I, flowing in a metallic wire and the potential difference across its terminals. The po-tential difference, V, across the ends of a given metallic wire in an electric circuit is directly pro-portional to the current flowing through it, pro-vided its temperature remains the same. This is called Ohm’s law.

8. The correct order of resistivity is:
(a) Conductor > Insulator > Alloy
(b) Alloy > Conductor > Insulator
(c) Insulator > Alloy > Conductor
(d) Insulator > Conductor > Alloy

Explanation:
The SI unit of resistivity isflm. It is a characteristic property of the material. The metals and alloys have very low resistivity in the range of 10-8 £1 m to 10-6 £1 m. They are good conductors of electricity. Insulators like rubber and glass have resistivity of the order of 10{powerl2) to 10(powerl7) £2 m. Both the resistance and resis-tivity of a material vary with temperature.

### Magnetic effects of electric current MCQ Questions

1. Consider the following statements about magnetic field :
1. Magnetic field is a quantity that has magnitude but not direction.
2. The direction of the magnetic field is taken to be the direction in which a north pole of the compass needle moves inside it
3. The relative strength of the magnetic field is shown by the degree of closeness of the field lines.
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 1 and 3
(c) 2 and 3
(d) 1, 2 and 3

Explanation:
Magnetic field is a quantity that has both direction and magnitude. The direction of the magnetic field is taken to be the direction in which the north pole of the compass needle moves inside it. Therefore, it is taken by convention that the field lines emerge from north pole and merge at the south pole (note the arrows marked on the field lines. The relative strength of the magnetic field is shown by the degree of closeness of the field lines. The field is stronger, that is, the force acting on the pole of another magnet placed is greater where the field lines are crowded.

2. Which of the following is/are correctly matched?
1. Magnetic field around conductor ______ righthand thumb rule.
2. Force on current carrying conductor ______ Fleming right hand rule.
3. Electric generator ______ electromagnetic Induction.
4. Electric motor ______ magnetic effect.
Choose the correct option from the codes given below:
(a) 1,2 and 4
(b) 1, 2 and 3
(c) 1,3 and 4
(d) 1, 2, 3 and 4

Explanation:
An electric current through a metallic conductor produces a magnetic field around it. A convenient way of finding the direction of magnetic field is associated with a current-carrying conductor. Imagine that you are holding a current-carrying straight conductor in your right hand such that the thumb points towards the direction of current. Then your fingers will wrap around the conductor in the direction of the field lines of the magnetic field. This is known as the right-hand thumb rule. According to Fleming left hand rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the first finger points in the direction of magnetic field and the second finger in the direction of current, then the thumb will point in the direction of motion or the force acting on the conductor. An electric motor is a rotating device that converts electrical energy to mechanical energy. Based on the phenomenon of electromagnetic induction, in an electric generatoi’, mechanical energy is used to rotate a conductor in a magnetic field to produce electricity.

3. Consider the following statements about solenoid :
1. A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder
2. The field lines inside the solenoid are in the form of parallel straight lines.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid. The field lines inside the solenoid are in the form of parallel straight lines. This indicates that the magnetic field is the same at all points inside the solenoid. That is, the field is uniform inside the solenoid. A strong magnetic field produced inside a solenoid can be used to magnetise a piece of magnetic material, like soft
iron, when placed inside the coil. The magnet so formed is called an electromagnet.

4. Consider the statements about force on current cariying conductor :
1. It was given by Alexandra Volta.
2. It is determined by Fleming Left hand Rule. Choose the correct option from the codes given below :
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
An electric current flowing through a conductor produces a magnetic field. The field so produced exerts a force on a magnet placed in the vicinity of the conductor. French scientist Andre Marie Ampere (1775-1836) suggested that the magnet must also exert an equal and opposite force on the current-canying conductor. The direction of the current and that of the magnetic field are perpendicular to each other and the force is per-pendicular to both of them. The three directions can be illustrated through a simple rule, called Fleming’s left-hand rule.

### Sources of Energy MCQ Questions

1. Consider the following statements about good source of energy :
1. It would do a large amount of work per unit volume or mass.
2. It should be easily accessible
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
A good source of energy would be one-
• which would do a large amount of work per unit volume or mass,
• be easily accessible,
• be easy to store and transport, and
• perhaps most importantly, be economical.

2. Which of the following is/are correct about wind energy ?
1. It is an environment-friendly and efficient source of renewable energy.
2. The wind speed should also be higher than 25 km/h to maintain the required speed of the turbine.
3. It requires no recurring expenses for the pro-duction.
Choose the correct option from the codes given below:
(a) 1,2 and 3
(b) 1 and 2
(c) 1 and 3
(d) 2 and 3

Explanation:
Wind energy is an environment-friendly and efficient source of renewable energy. It requires no recurring expenses for the production of electricity. But there are many limitations in harnessing wind energy. Firstly, wind energy farms can be established only at those places where wind blows for the greater part of a year. The wind speed should also be higher than 15 km/h to maintain the required speed of the turbine. Furthermore, there should be some back-up facilities (like storage cells) to take care of the energy needs during a period when there is no wind. Establishment of wind energy farms requires large area of land.

3. Which of the following is/are correct about solar cooker?
1. Solar cookers achieve a higher temperature by using mirrors to focus the rays of the Sun.
2. It works on the principle that a black surface absorbs more heat.
Choose the correct option from the codes given below:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Explanation:
A black surface absorbs more heat as compared to a white or a reflecting surface under identical conditions. Solar cookers and solar water heaters use this property in their working. Some solar cookers achieve a higher temperature by using mirrors to focus the rays of the Sun. Solar cookers are covered with a glass plate.

4. Which of the following is/are correctly matched?
1. Tidal energy ______ gravitational pull of moon
2. Wave energy ______ potential energy of waves
3. Ocean Thermal energy ______ difference in temperature of water
Choose the correct option from the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3