MCQ Questions Archives

MCQ Questions for Class 9 Science Chapter 14 Natural Resources with Answers

October 27, 2021July 20, 2020 by Kishen

MCQ Questions for Class 9 Science Chapter 14 Natural Resources with Answers

MCQs from Class 9 Science Chapter 14 – Natural Resources are provided here to help students prepare for their upcoming Science exam.

MCQs from CBSE Class 9 Science Chapter 14: Natural Resources

Q1. What would happen, if all the oxygen present in the environment is converted to ozone?
(a) We will be protected more
(b) It will become poisonous and kill all living forms
(c) Ozone is not stable, hence it will be toxic
(d) It will allow harmful sun radiations to reach earth and damage many life forms

Answer/ Explanation

(b) It will become poisonous and kill all living forms

Q2.When we breathe in air, nitrogen also goes inside along with oxygen. What is the fate of nitrogen?
(a) It moves along with oxygen into the cells
(b) It comes out with the carbon dioxide during exhalation
(c)It is absorbed only by the nasal cells
(d) Nitrogen concentration is already more in the cells, so itis not at all absorbed

Answer/ Explanation

(b) It comes out with the carbon dioxide during exhalation

Q3. There is always a cycle of CO₂ running in the atmosphere due to which the concentration of CO2 remains constant in the atmosphere. Choose the correct sequence of this cycle:
(a) CO₂ in atmosphere→ decomposers → organic carbon in animals → inorganic carbon in soil
(b) CO₂ in atmosphere → organic carbon in plants →organic carbon in animals → inorganic carbon in soil
(c)Inorganic carbonates in water →organic carbon in plants → organic carbon in animals → scavengers.
(d) Organic carbon in animals → decomposers → CO₂ in atmosphere →organic carbon in plants

Answer/ Explanation

(b) CO₂ in atmosphere → organic carbon in plants →organic carbon in animals → inorganic carbon in soil

Q4. You must have observed that during the winters sometimesit becomes quite difficult to see even the objects short distance apart. This low visibility during the cold weather is due to:
(a) Formation of fossil fuels
(b) Unburnt carbon particles of hydrocarbons suspended in air
(c) Lack of adequate power supply
(d) None of these

Answer/ Explanation

(b) Unburnt carbon particles of hydrocarbons suspended in air

Q5. The ‘water pollution’ can be defined in several ways. Which of the following statements does not give the correct definition?
(a) The addition of the undesirable substances to water bodies
(b) The removal of the desirable substances from water bodies
(c)A change in pressure of the water bodies
(d) A change in temperature of the water bodies

Answer/ Explanation

Q6. The amount of nitrogen in the atmosphere is maintained by a biological cycle which involves two processes, first is to withdraw nitrogen from the atmosphere and secondly to add the same to atmosphere.

The nitrogen cycle
Can you guess the names of these two respective processes.
(a) Nitrogen fixation and nitrification
(b) Nitrogen fixation and denitrification
(c)Nitrification and denitrification
(d) Nitrification and nitrogen fixation

Answer/ Explanation

(b) Nitrogen fixation and denitrification

Q7. Ozone layer is a protective blanket in the atmosphere that protectsus from the harmful high energy UV radiations coming from the sun. But it has been observed that some harmful air pollutants like chlorofluorocarbons are causing hole in this protective layer. What does this ‘ozone hole’ exactly mean?
(a) A large sized hole in the ozone layer
(b) Thinning of the ozone layer
(c)Small holes scattered in the ozone layer
(d) Thickening of the layer

Answer/ Explanation

(b) Thinning of the ozone layer

Q8. Aquatic organisms are used to a certain range of temperature in the water bodies where they live. A sudden marked change in this temperature can affect:
i. Breeding of animals
ii. Growth of the aquatic plants
iii. Process of digestion in animals
iv. Availability of nutrients
Choose the correct option from the following:
(a) (i) and (ii)
(b) (i) and (iv)
(c) Only (ii)
(d) (ii) and (iii)

Answer/ Explanation

(a) (i) and (ii)

Q9. Presence of the fertilizers and sewage in polluted water provides a lot of nitrogen, causing excessive growth of algae which subsequently reduces the amount of dissolved oxygen in water.Can you name this process of reduction of dissolved oxygen due to the excess growth of algae.
(a) Biomagnifications
(b) Eutrophication
(c)Algal bloom
(d) Decopmposition

Answer/ Explanation

(b) Eutrophication

Q10. A cool breeze after a hot day brings all of us considerable relief. This breeze is actually the moving air. What is the basic process that causes this movement of air?
(a) Pressure difference between the air of two regions
(b) Moving leaves of the plants
(c)Temperature difference between the two regions
(d) Striking of air with the mountains

Answer/ Explanation

Q11. If the carbon dioxide content in the atmosphere is increased then which one of the following would not get affected?
(a) Amount of the heat retained by the environment
(b) Process of photosynthesis in plants
(c) Global warming
(d) Existence of desert plants

Answer/ Explanation

(d) Existence of desert plants

Q12.The nitrogen molecules present in air can be converted into nitrates by:
(a) A biological process of nitrogen fixing bacteria present in the soil
(b) A biological process of carbon fixing factor present in the soil
(c) Any of the industries manufacturing nitrogenous compounds
(d) The plants used as cereal crops in field

Answer/ Explanation

(a) A biological process of nitrogen fixing bacteria present in the soil

Q13. Top soil is the best for the vegetation. The main components ofthis productive top layer are:
(a) Humus and living organisms only
(b) Humus and soil particles only
(c) Humus, living organisms and plants
(d) Humus, living organisms and soil particles

Answer/ Explanation

(b) Humus and soil particles only

Q14. The process of nitrogen fixation by bacteria does not take place in the presence of:
(a) Molecular form of hydrogen
(b) Elemental form of oxygen
(c) Water
(d) Elemental form of nitrogen

Answer/ Explanation

(b) Elemental form of oxygen

Q15. Following is the diagram showing the natural Ecosystem comprising both of abiotic as well as biotic components.

The Biotic components of an ecosystem consist of:
(a) Producers
(b) Consumers
(c) Decomposers
(d) All of these

Answer/ Explanation

(d) All of these

MCQ Questions for Class 9 Science Chapter 13 Why Do We Fall Ill with Answers

October 27, 2021July 20, 2020 by Kishen

MCQ Questions for Class 9 Science Chapter 13 Why Do We Fall Ill with Answers

MCQs from Class 9 Science Chapter 13 – Why Do We Fall Ill are provided here to help students prepare for their upcoming Science exam.

MCQs from CBSE Class 9 Science Chapter 13: Why Do We Fall Ill

Q1. You are aware of Polio Eradication Programme in your city. Children are vaccinated because
(a) Vaccination kills the polio causing microorganisms
(b) Prevents the entry of polio causing organisms in the body
(c)It creates immunity in the body
(d) All of above

Answer/ Explanation

Q2. Making anti-viral drugs is more difficult than making anti-bacterial medicines because
i. Viruses make use of host machinery
ii. Viruses are on the border line of living and non-living
iii. Viruses have very few biochemical mechanisms of their own
iv. Viruses have a protein coat
Choose the correct option among the following:
(a) (i) and (iii)
(b) only(iii)
(c) (ii) and (iv)
(d) only(iv)

Answer/ Explanation

(b) only (iii)

Q3. Many of the people suffer from the problem of acnes and feel annoyed of the ugly skin texture caused due to the acne spots. Can you guess the microorganism causing these acne?
(a) H1N1 virus
(b) Trypanosoma
(c)Leishmania
(d) Staphylococcus

Answer/ Explanation

(d) Staphylococcus

Q4. If you live in an overcrowded and poorly ventilated house, then you may suffer from which of the following diseases?
i. Cholera
ii. AIDS
iii. Air borne disease
iv. Cancer
Choose the correct option among the following:
(a) (i) and (iii)
(b) (ii) and (iii)
(c) only(iii)
(d) only (iv)

Answer/ Explanation

Q5. Antibiotics are ineffective against the viral infections. For each type of the viral infection, human body produces its own antiviral protein that is released from the infected and dying host cells. What is this protein called?
(a) Interferon
(b) Leishmania
(c) Ascaris
(d) Pertussis

Answer/ Explanation

(a) Interferon

Q6. Cancer is a disease caused due to the uncontrolled growth of tissues in any part of body. This disease comes under which of the following types?
(a) Congenital disease
(b) Infectious disease
(c)Non-infectious disease
(d) None of these

Answer/ Explanation

Q7. The main symptoms of the HIV-AIDS infection are due to the fact that patient’s body can no longer fight off many minor infections and hence becomes the reason of the patient’s ultimate death.
This happens because:
(a) HIV virus alone causes all the infections
(b) HIV virus releases a poison in the body
(c) HIV virus damages the immune system of the body
(d) HIV virus directly attacks the human nervous system

Answer/ Explanation

Q8. Tuberculosis is a disease which spreads from one person to another directly or indirectly is diagnosed with the help of a protein extracted from a bacterium called Mycobacterium tuberculosis which also causes the disease. What is the name of this protein?
(a) Tuberlysis
(b) Rifampicin
(c) Cephalosporin
(d) Tuberculin

Answer/ Explanation

(d) Tuberculin

Q9. Cholera is an infectious, fatal disease caused by the bacterium which lives and multiplies in the small intestine. The disease sometimes occurs in epidemic form. Which of the following is not a reason for the spread of the disease?
(a) Breeding of the flies on the garbage heaps
(b) Use of spices in food
(c)Drinking the contaminated water
(d) Consuming the contaminated food

Answer/ Explanation

(b) Use of spices in food

Q10. For the prevention of the dehydration, the patient is advised to take Oral Rehydration Solution (ORS). The main components of ORS solution are:
(a) Sodium chloride, sodium bicarbonate, potassium chloride, glucose, sucrose and water
(b) Sodium chloride, sodium carbonate, potassium chloride, glucose,sucrose and water
(c)Sodium carbonate, sodium bicarbonate, potassium chloride, glucose,sucrose and water
(d) Sodium chloride, sodium bicarbonate, potassium chloride, glucose,sucrose and water

Answer/ Explanation

(a) Sodium chloride, sodium bicarbonate, potassium chloride, glucose, sucrose and water

Q11. TAB-vaccine is used to provide immunity against Typhoid for a period of three years.What is the correct abbreviation of TAB?
(a) Typhoid-Paratyphoid A and B Vaccine
(b) Typhoid-Partialtyphoid A and B Vaccine
(c)Typhoid-Peroxytyphoid A and B Vaccine
(d) Typhoid-Pertyphoid A and B Vaccine

Answer/ Explanation

(a) Typhoid-Paratyphoid A and B Vaccine

Q12. Water makes averagely about 60% part of human body and is necessary in every biochemical reaction occurring in human body. Which of the following is a disease which is caused due to the loss of water in the body making the patient seriously ill in a very short time?
(a) Rehydration
(b) Hydration
(c)Dehydration
(d) Hydrolysis

Answer/ Explanation

Q13. Which of the following is an incorrect statement about tuberculosis?
i. It is caused by Salmonella
ii. It commonly affects immune system
iii. Bacteria release tuberculin toxin
iv. Patient’s sputum contains blood
Choose the correct option among the following:
(a) (ii) and (iii)
(b) Only (ii)
(c) (iii) and (iv)
(d) (i) and (ii)

Answer/ Explanation

(d) (i) and (ii)

Q14. Mosquitoes are often seen breeding on the stagnant water. We should not allow mosquitoes to breed in our surroundings because they
(a) multiply very fast and cause pollution
(b) are vectors for many diseases
(c) bite and cause skin diseases
(d) are not important insects

Answer/ Explanation

(b) are vectors for many diseases

Q15. Infectious diseases are the diseases that can spread from infected person to the healthy person. Which of the following can make you ill if you come in contact with an infected person?
(a) Genetic abnormality
(b) Blood cancer
(c) High blood pressure
(d) Sneezing and coughing

Answer/ Explanation

(d) Sneezing and coughing

MCQ Questions for Class 9 Science Chapter 12 Sound with Answers

October 27, 2021July 20, 2020 by Kishen

MCQ Questions for Class 9 Science Chapter 12 Sound with Answers

MCQs from Class 9 Science Chapter 12 – Sound are provided here to help students prepare for their upcoming Science exam.

MCQs from CBSE Class 9 Science Chapter 12: Sound

Q1. The sound can travel in air when:
(a) Particles of medium travel from one place to another
(b) There is no moisture in the atmosphere
(c) Disturbance travel from one place to another
(d) Both particles as well as disturbance travel from one place to another

Answer/ Explanation

Q2. We can distinguish between a man’s voice and a woman’s voice of the same loudness even without seeing them. This is due to a characteristic of sound which measures the shrillness of sounds. Can you choose the correct unit of the quantity on which this characteristic of sound depends?
(a) hertz
(b) meter/second
(c) meter
(d) unitless

Answer/ Explanation

(a) hertz

Q3. A key of mechanical piano is first struck gently and then struck again but much harder this time. What kind of change in sound will you observe in the second case:
(a) Sound will be louder but the pitch will not be different
(b) Sound will be louder and the pitch will also be higher
(c) Sound will be louder but the pitch will be lower
(d) Both loudness and pitch will remain unaffected

Answer/ Explanation

Q4. The echo-receiver of a sonar attached to a ship, receives the echo from the bottom of sea 4 seconds after the ultrasonic waves were sent into the sea.

If the speed of sound in water is 1500 m/s, then what is the depth of the sea?
(a) 6000 m
(b) 3000 m
(c) 15000 m
(d) 3500 m

Answer/ Explanation

(b) 3000 m

Q5. Before the main shock waves, the earthquake produces the characteristic sound waves which some animals like rhinoceros can hear. Can you guess the kind of sound waves produced here?
(a) Infrasonic sounds
(b) Ultrasonic sounds
(c) Audible Sounds
(d) None of these

Answer/ Explanation

(a) Infrasonic sounds

Q6. Given below is the diagram of human ear. Choose the correct labeling of the parts A, B and C.

(a) A-ear lobe, B-ear canal, C-auditory nerve
(b) A-ear drum, B-auditory nerve, c-ear canal
(c) A-ear canal, B-Eustachian tube, C-auditory nerve
(d) A-ear canal, B-Eustachian tube, C-cochlea

Answer/ Explanation

Q7. On increasing the temperature, the speed of sound in air:
(a) Increases
(b) Decreases
(c) Does not change
(d) First increases then becomes constant

Answer/ Explanation

(a) Increases

Q8. Loudness measures the sound energy reaching the ear per second and depends on the amplitude of the sound wave. What is the unit used to measure the loudness of sound?
(a) hertz
(b) decibel
(c) meter/second
(d) second

Answer/ Explanation

(b) decibel

Q9. We can easily distinguish between the sounds of the different singers even without having seen them. This is all due the different quality or timber of their sounds. On what factor does the quality of sound depend?
(a) Wavelength
(b) Waveform
(c) Wave frequency
(d) Wave amplitude

Answer/ Explanation

(b) Waveform

Q10. Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the string suitably. By doing so, he is adjusting
i. Amplitude of the sound
ii. Frequency of the sitar string with the frequency of other musical instruments
iii. Intensity of sound
iv. Loudness of sound
Choose the correct option:
(a) (i) and (iii)
(b) only (ii)
(c) (ii) and (iv)
(d) only (iv)

Answer/ Explanation

(b) only (ii)

Q11. The bats can fly in the darkness of night without colliding with the other objects by emitting special sounds while flying. Which characteristic of sound is used by the bats to navigate?
(a) Ultrasound
(b) Infrasound
(c) Audible sound
(d) None of these

Answer/ Explanation

(a) Ultrasound

Q12. The sound travels from particle to particle in the form of vibrations and has different speeds in different mediums.

The maximum speed of vibrations which produce audible sound will be in:
(a) Sea water
(b) Ground glass
(c) Human blood
(d) Dry air

Answer/ Explanation

(b) Ground glass

Q13. Which of the following can produce longitudinal as well as transverse waves under different conditions?
(a) Bats
(b) Slinky
(c) Tuning fork
(d) None of these

Answer/ Explanation

(b) Slinky

Q14. If the speed of a wave is 380 m/s and its frequency is 1900 Hz, then the wavelength of the wave will be:
(a) 20 m
(b) 0.2 m
(c) 200 m
(d) 2 m

Answer/ Explanation

(b) 0.2 m

Q15. You must have seen the doctor checking the sounds produced in the chest or heartbeat of a patient using a medical instrument called Stethoscope. On what principle does this Stethoscope work?
(a) Multiple refractions
(b) Multiple reflections
(c) Wave motion
(d) None of these

Answer/ Explanation

(b) Multiple reflections

MCQ Questions for Class 9 Science Chapter 11 Work and Energy with Answers

October 27, 2021July 20, 2020 by Kishen

MCQ Questions for Class 9 Science Chapter 11 Work and Energy with Answers

MCQs from Class 9 Science Chapter 11 – Work and Energy are provided here to help students prepare for their upcoming Science exam.

MCQs from CBSE Class 9 Science Chapter 11: Work and Energy

1. A man is carrying the heavy luggage from one platform to the other of a Railway station but still according to the logics of science his work done is said to be zero. Can you opt out the correct reason?
(a) The force is acting along the direction of displacement of luggage
(b) The force is acting perpendicular to the direction of displacement of luggage
(c) The force is acting opposite to the direction of displacement of luggage
(d) None of these

Answer/ Explanation

(b) The force is acting perpendicular to the direction of displacement of luggage

2. When a body falls freely towards the earth, then its total energy
(a) Decreases
(b) Increases
(c) First increases and then decreases
(d) Remains constant

Answer/ Explanation

(d) Remains constant

3. When a body like earth is moving in a circular path the work done in that case is zero because:
(a) Centripetal force acts in the direction of motion of the body
(b) Centripetal force acts along the radius of circular path
(c) Gravitational force acts along the radius of circular path
(d) Centrifugal force acts perpendicular to the radius of circular path

Answer/ Explanation

(b) Centripetal force acts along the radius of circular path

4. A car is accelerated on a leveled road and attains a velocity 4 times of its initial velocity. In this process, the kinetic energy of the car
(a) Becomes twice to that of the initial
(b) Becomes four times to that of the initial
(c) Remains the same
(d) Becomes 16 times to that of the initial

Answer/ Explanation

(d) Becomes 16 times to that of the initial

5. The momentum of a bullet of mass 20 g fired from a gun is 10 kg m/s. The kinetic energy of this bullet in kJ will be:
(a) 25
(b) 2.5
(c) 0.25
(d) 5

Answer/ Explanation

(b) 2.5

6. Which one of the following is not the unit of energy?
(a) Kilowatt
(b) Kilowatt hour
(c) Joule
(d) Newton meter

Answer/ Explanation

(a) Kilowatt

7. The form of energy possessed by a flying bird is:
(a) Kinetic energy
(b) Potential energy
(c) Both kinetic and potential energy
(d) Can’t say

Answer/ Explanation

8. In the dams water is stored in the high reservoirs and then made to fall down. This falling water then rotates the turbines to generate electricity. In this energy conversion process can you tell the initial and final energies respectively?
(a) Kinetic energy and electrical energy
(b) Potential energy and kinetic energy
(c) Potential energy and electrical energy
(d) Kinetic energy and potential energy

Answer/ Explanation

(a) Kinetic energy and electrical energy

9. A man of mass 50 kg jumps to a height of 1 m. His potential energy at the highest point is(g = 10 m/s²):
(a) 50 J
(b) 500 J
(c) 5 J
(d) 5000 J

Answer/ Explanation

(b) 500 J

10. The type of energy possessed by a simple pendulum, when it is at the mean position is:
(a) Kinetic energy
(b) Potential energy
(c) Kinetic + Potential energy
(d) Sound energy

Answer/ Explanation

(a) Kinetic energy

11. A body is falling from a height h. After it has fallen to a height of h/2, it will possess:
(a) Only kinetic energy
(b) Half kinetic and half potential energy
(c) Only potential energy
(d) More kinetic and less potential energy

Answer/ Explanation

(d) More kinetic and less potential energy

12. Two objects of masses 1 × 10^-3kg and 4 × 10^-3 kg have equal momentum. What is the ratio of their kinetic energies?
(a) 2:1
(b) 4:1
(c) 1:4
(d) 1:2

Answer/ Explanation

(b) 4:1

13. The work done on an object does not depend upon the:
(a) Angle between force and displacement
(b) Force applied
(c) Initial velocity of the object
(d) Displacement

Answer/ Explanation

14. An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are 10 m above the ground, they have the same:
(a) Potential energy
(b) Momenta
(c) Acceleration
(d) Kinetic energy

Answer/ Explanation

15. A microphone converts:
(a) Sound energy into mechanical energy in stereo system
(b) Sound energy into electrical energy in public address system
(c) Electrical energy into sound energy in ordinary telephone
(d) Microwave energy into sound energy in a mobile phone

Answer/ Explanation

(b) Sound energy into electrical energy in public address system

16. Which of the following energy change involves frictional force?
i. Potential energy to sound energy
ii. Chemical energy to heat energy
iii. Kinetic energy to heat energy
iv. Chemical energy to heat energy
Choose the correct option among the following:
(a) Both (i) and (ii)
(b) Only (iv)
(c)Both (ii) and (iii)
(d) Only (iii)

Answer/ Explanation

(d) Only (iii)

MCQ Questions for Class 9 Science Chapter 10 Gravitation with Answers

October 27, 2021July 19, 2020 by Kishen

MCQ Questions for Class 9 Science Chapter 10 Gravitation with Answers

MCQs from Class 9 Science Chapter 10 – Gravitation are provided here to help students prepare for their upcoming Science exam.

MCQs from CBSE Class 9 Science Chapter 10: Gravitation

1. The mass of moon is about 0.012 times that of the earth and its diameter is about 0.25 times that of earth. The value of G on the moon will be:
(a) Same as that on the earth
(b) About one-fifth of that on the earth
(c) About one-sixth of that on the earth
(d) About one-fourth of that on the earth

Answer/ Explanation

(a) Same as that on the earth

2. An apple falls from a tree because of the gravitational attraction between the earth and the apple. If F1 is the magnitude of the force exerted by the earth on the apple and F2 is the magnitude of the force exerted by the apple on the earth, then
(a) F1 is very much greater than F2
(b) F2 is very much greater than F1
(c) F1 and F2 are equal
(d) F1 is only a little greater than F2

Answer/ Explanation

3. The earth and the moon are attracted to each other by gravitational force. The earth attracts the moon with a force that is:
(a) More than that exerted by the moon
(b) Same as that exerted by the moon
(c) Less than that exerted by the moon
(d) Not related to that exerted by the moon

Answer/ Explanation

(b) Same as that exerted by the moon

4. A stone is released from the top of a tower of height 19.6 m. Then its final velocity just before touching the ground will be:
(a) 384.16 m/ s
(b) 196 m/s
(c) 19.6 m/s
(d) 3841.4 m/s
(Take g = 9.8 m/s²)

Answer/ Explanation

5. When a piece of cork is put into the water it starts floating on the surface of water due to the upward buoyant force from water.

If the cork is pushed more inside the water by applying the force than the buoyant force:
(a) Will increase as the cork is immersed into the water
(b) Will decrease as the cork is immersed into the water
(c) Will first increase and then decrease as the cork is immersed more into the water
(d) Will remain the same as long as the cork is inside the water

Answer/ Explanation

(a) Will increase as the cork is immersed into the water

6. A rectangular wooden block has the length, breadth and height of 40 cm, 35 cm and 10 cm, respectively. This wooden block is kept on ground in three different ways, turn by turn.

Which of the following is the correct statement about the pressure exerted by this block on the ground?
(a) The maximum pressure is exerted when the length and breadth form the base
(b) The maximum pressure is exerted when the length and height form the base
(c) The maximum pressure is exerted when the breadth and height form the base
(d) The maximum pressure is exerted when the length and height form the base

Answer/ Explanation

7. Two particles are placed at some distance. If the mass of each of the two particles is doubled, keeping the distance between them unchanged, the value of gravitational force between them will be:
(a) 1/4 times
(b) 4 times
(c) 1/2 times
(d) Unchanged

Answer/ Explanation

(b) 4 times

8. A boy is whirling a stone tied with a string in a horizontal circular path as shown in the following figure:

If the string breaks the stone:
(a) Will move along a straight line towards the centre of the circular path
(b) Will move along a straight line the tangential to the circular path
(c) Will move along a straight line perpendicular to the circular path away from the boy
(d) Will continue to move in the circular path

Answer/ Explanation

(b) Will move along a straight line the tangential to the circular path

9. Following table represents the mass and volume data of the three liquids named A, B, C and D. Can you find which two liquids are identical?

Liquid	Mass (in g)	Volume (in cm³)
A	80	100
B	100	100
C	80	80
D	100	80

(a) A and C
(b) B and C
(c) A and D
(d) B and D

Answer/ Explanation

(b) B and C

10. A ball weighing 4 kg of density 4000 kgm^-3 is completely immersed in water of density10³ kgm^-3. What will be the buoyant force acting on it?
(a) 100 N
(b) 10 N
(c) 1600N
(d) 16 N

Answer/ Explanation

(b) 10 N

11. Choose the correct unit for the relative density among the following:
(a) kg/cm
(b) unitless
(c) kg/cm
(d) kg/m³

Answer/ Explanation

(b) unitless

12. An object having mass equal to 350 g occupies 200 cm³ of the space. When this object is thrown into a river what will be the condition of this object there? (Density of water = 1 g/ cm³)
(a) It will float on the surface of water
(b) It will float fully submerged in the liquid
(c) It will sink in the liquid
(d) It will float partially submerged in the liquid

Answer/ Explanation

13. An object is put in three liquids having different densities, one by one. The object floats with 1/9, 2/11 and 3/7 parts of its volume outside the surface of liquids of densities d1, d2 and d3 respectively. Which of the following is the correct order of the densities of three liquids?
(a) d1 > d2 > d3
(b) d2 > d3 > d1
(c) d1 < d2 < d3
(d) d3 > d2 > d1

Answer/ Explanation

14. The school bags are generally provided with the broad strips because:
(a) It will spread the force of the bag over the large area of the shoulder of the child producing large pressure
(b) It will spread the force of the bag over the large area of the shoulder of the child producing less pressure
(c) It has become a trend among the students to carry the bags with wide strips
(d) It will spread the force of the bag over the small area of the shoulder of the child producing less pressure

Answer/ Explanation

(b) It will spread the force of the bag over the large area of the shoulder of the child producing less pressure

15. Two objects of different masses falling freely near the surface of moon would:
(a) Have different accelerations
(b) Undergo a change in their inertia
(c) Have same velocities at any instant
(d) Experience forces of same magnitude

Answer/ Explanation

MCQ Questions for Class 9 Science Chapter 9 Force and Laws of Motion with Answers

October 27, 2021July 19, 2020 by Kishen

MCQ Questions for Class 9 Science Chapter 9 Force and Laws of Motion with Answers

MCQs from Class 9 Science Chapter 9 – Force and Laws of Motion are provided here to help students prepare for their upcoming Science exam.

MCQs from CBSE Class 9 Science Chapter 9: Force and Laws of Motion

1. A goalkeeper in a game of football pulls his hands backwards after holding the ball shot at the goal. This enables the goalkeeper to:
(a) Exert large force on the ball
(b) Increases the force exerted by the ball on hands
(c) Increase the rate of change of momentum
(d) Decrease the rate of change of momentum

Answer/ Explanation

(d) Decrease the rate of change of momentum

2. An object of mass 2 kg is sliding with a constant velocity of 4 m/s on a friction less horizontal table. The force required to keep the object moving with the same velocity is:
(a) 32 N
(b) 0 N
(c) 2 N
(d) 8 N

Answer/ Explanation

(b) 0 N

3. Newton’s third law of motion explains the two forces namely ‘action’ and ‘reaction’ coming into action when the two bodies are in contact with each other. These two forces:

(a) Always act on the same body
(b) Always act on the different bodies in opposite directions
(c) Have same magnitude and direction
(d) Acts on either body at normal to each other

Answer/ Explanation

(b) Always act on the different bodies in opposite directions

4. In a rocket, a large volume of gases produced by the combustion of fuel is allowed to escape through its tail nozzle in the downward direction with the tremendous speed and makes the rocket to move upward.

Which principle is followed in this take off of the rocket?
(a) Moment of inertia
(b) Conservation of momentum
(c) Newton’s third law of motion
(d) Newton’s law of gravitation

Answer/ Explanation

(b) Conservation of momentum

5. A water tank filled upto 2/3 of its height is moving with a uniform speed. On sudden application of the brake, the water in the tank would
(a) Move backward
(b) Move forward
(c) Come to the rest
(d) Be unaffected

Answer/ Explanation

(b) Move forward

6. Velocity versus time graph of a ball of mass 50 g rolling on a concrete floor is shown in the figure below. What will be the frictional force of the floor on the ball?

(a) 0.5 N
(b) 50 N
(c) 5 N
(d) 0.05 N

Answer/ Explanation

(a) 0.5 N

7. The seat belts are provided in the cars so that if the car stops suddenly due to an emergency braking, the persons sitting on the front seats are not thrown forward violently and saved from getting injured. Can you guess the law due to which a person falls in forward direction on the sudden stopping of the car?
(a) Newton’s first law of motion
(b) Newton’s second law of motion
(c) Newton’s third law of motion
(d) Newton’s law of gravitation

Answer/ Explanation

(a) Newton’s first law of motion

8. When a balloon held between the hands is pressed, its shape changes. This happens because:
(a) Balanced forces act on the balloon
(b) Unbalanced forces act on the balloon
(c) Frictional forces act on the balloon
(d) Gravitational force acts on the balloon

Answer/ Explanation

(a) Balanced forces act on the balloon

9. Which of the following situations involves the Newton’s second law of motion?
(a) A force can stop a lighter vehicle as well as a heavier vehicle which are moving
(b) A force exerted by a lighter vehicle on collision with a heavier vehicle results in both the (vehicles coming to a standstill
(c) A force can accelerate a lighter vehicle more easily than a heavier vehicle which are moving
(d) A force exerted by the escaping air from a balloon in the downward direction makes the balloon to go upwards

Answer/ Explanation

10. The speed of a car weighing 1500 kg increases from 36 km/h to 72 km/h uniformly. What will be the change in momentum of the car?
(a) 15000 kg km/h
(b) 15000 kg m/s
(c) 54000 kg m/s
(d) 54000 g m/s

Answer/ Explanation

(b) 15000 kg m/s

11. A passenger in a moving train tosses a coin which falls behind him. Observing this statement what can you say about the motion of the train?
(a) Accelerated
(b) Retarded
(c) Along circular tracks
(d) Uniform

Answer/ Explanation

(a) Accelerated

12. Newton’s first law of motion says that a moving body should continue to move forever , unless some external forces act on it. But a moving cycle comes to rest after some time if we stop pedaling it. Can you choose the correct reason for the stoppage of cycle?
i. Air resistance
ii. Gravitational pull of the earth
iii. Friction of the road
iv. Heat of the environment
Choose the correct option:
(a) (iii) and (iv)
(b) (i) and (iii)
(c) (i) and (ii)
(d) (ii) and (iii)

Answer/ Explanation

(b) (i) and (iii)

13. A man wearing a bullet-proof vest stands on roller skates. The total mass is 80 kg. A bullet of mass 20 g is fired at 400 m/s. It is stopped by the vest and falls to the ground. What is then the velocity of the man?
(a) 1 m/s
(b) 0.1 m/s
(c) 0.01 m/s
(d) 0 m/s

Answer/ Explanation

(b) 0.1 m/s

14. The unit of measuring the momentum of a moving body is:
(a) m/s
(b) kg.m/s
(c) kg.m/s²
(d) N m²/kg²

Answer/ Explanation

(b) kg.m/s

15. The inertia of a moving object depends on:
i. Mass of the object
ii. Momentum of the object
iii. Speed of the object
iv. Shape of the object

Choose the correct option:
(a) (i) and (ii)
(b) only (i)
(c) only (ii)
(d) (iii) and (iv)

Answer/ Explanation

(b) only (i)