Explore the world of work and energy with our vast repository of 1000+ work and energy MCQs, accompanied by explanations, catering to Class 9 students seeking clarity on kinetic energy, potential energy, and work-energy theorem.

## 100+ Work And Energy MCQs with Explanations for Class 9

Immerse yourself in the realm of Work and Energy with our meticulously crafted MCQs. Designed for Class 9 students, this expansive collection of over 100+ MCQs, supplemented with explanations, serves as a valuable tool for mastering kinetic energy, potential energy, and work-energy theorem concepts.

- Which of the following best defines work in physics?

A) The amount of force exerted on an object

B) The displacement of an object in the direction of the force applied to it

C) The energy possessed by an object at rest

D) The speed of an object in motion

Correct Option: B

Explanation: Work is defined as the product of force and displacement in the direction of the force. - Which form of energy is associated with motion?

A) Potential energy

B) Kinetic energy

C) Chemical energy

D) Thermal energy

Correct Option: B

Explanation: Kinetic energy is the energy possessed by an object due to its motion. - If an object is raised to a certain height above the ground, which type of energy does it possess?

A) Kinetic energy

B) Potential energy

C) Chemical energy

D) Electrical energy

Correct Option: B

Explanation: Potential energy is associated with the position or height of an object. - In which of the following situations is work done?

A) Holding a book stationary in your hands

B) Pushing against a wall without moving it

C) Carrying a heavy bag while walking

D) All of the above

Correct Option: C

Explanation: Work is done when there is a displacement of an object in the direction of the applied force. - The ability to do work is known as:

A) Power

B) Energy

C) Force

D) Momentum

Correct Option: B

Explanation: Energy is the capacity to do work. - What is the SI unit of energy?

A) Joule

B) Newton

C) Watt

D) Kilogram

Correct Option: A

Explanation: Joule is the unit of energy. - Which of the following is a renewable source of energy?

A) Coal

B) Natural gas

C) Wind

D) Petroleum

Correct Option: C

Explanation: Wind energy is considered renewable because it is continuously replenished by nature. - What is the efficiency of a machine that performs 80 J of work with an input energy of 100 J?

A) 80%

B) 100%

C) 120%

D) 60%

Correct Option: A

Explanation: Efficiency is calculated as the ratio of output work to input energy, multiplied by 100%. - Which of the following is a non-renewable source of energy?

A) Solar energy

B) Hydroelectric energy

C) Nuclear energy

D) Biomass energy

Correct Option: C

Explanation: Nuclear energy is derived from radioactive materials and is considered non-renewable. - The rate at which work is done is known as:

A) Speed

B) Power

C) Energy

D) Momentum

Correct Option: B

Explanation: Power is defined as the rate at which work is done or energy is transferred. - Which of the following equations represents kinetic energy?

A)

B)

C)

D)

Correct Option: A

Explanation: Kinetic energy is calculated using the equation where m is mass and v is velocity. - A 2 kg object is moving with a velocity of 3 m/s. What is its kinetic energy?

A) 9 J

B) 12 J

C) 18 J

D) 6 J

Correct Option: C

Explanation: Using the formula for kinetic energy: , we find KE = J. - Which of the following is a unit of power?

A) Watt

B) Newton

C) Joule

D) Ohm

Correct Option: A

Explanation: Watt is the unit of power, named after James Watt. - What is the efficiency of a machine that outputs 600 J of work with an input energy of 800 J?

A) 75%

B) 80%

C) 60%

D) 150%

Correct Option: A

Explanation: Efficiency = (Output work / Input energy) × 100% = (600/800) × 100% = 75%. - Which of the following is a form of potential energy?

A) Thermal energy

B) Light energy

C) Gravitational energy

D) Sound energy

Correct Option: C

Explanation: Gravitational potential energy is associated with an object’s position relative to the Earth’s surface. - The SI unit of work is the same as the SI unit of:

A) Power

B) Energy

C) Force

D) Momentum

Correct Option: B

Explanation: Work and energy share the same unit, the joule (J). - What is the potential energy of a 5 kg object raised 10 meters above the ground?

A) 50 J

B) 100 J

C) 500 J

D) 200 J

Correct Option: C

Explanation: Potential energy = mgh = 5 kg × 10 m/s² × 10 m = 500 J. - A force of 20 N is applied to move a box a distance of 5 meters. How much work is done?

A) 25 J

B) 100 J

C) 4 J

D) 10 J

Correct Option: B

Explanation: Work = force × distance = 20 N × 5 m = 100 J. - Which of the following statements regarding energy conversion is correct?

A) Energy can be created but not destroyed

B) Energy can be destroyed but not created

C) Energy can neither be created nor destroyed

D) Energy can be created and destroyed freely

Correct Option: C

Explanation: According to the law of conservation of energy, energy cannot be created or destroyed, only converted from one form to another. - Which of the following is an example of potential energy?

A) A moving car

B) A stretched spring

C) A spinning top

D) A burning candle

Correct Option: B

Explanation: When a spring is stretched, it stores potential energy due to its position. - The efficiency of a machine is always expressed in:

A) Percentage

B) Newtons

C) Joules

D) Watts

Correct Option: A

Explanation: Efficiency is typically expressed as a percentage. - Which of the following is a renewable energy source?

A) Fossil fuels

B) Biomass

C) Nuclear energy

D) Natural gas

Correct Option: B

Explanation: Biomass is a renewable energy source derived from organic materials. - What is the power of a machine that does 500 J of work in 10 seconds?

A) 50 W

B) 5 W

C) 100 W

D) 5000 W

Correct Option: A

Explanation: Power = Work / Time = 500 J / 10 s = 50 W. - Which of the following is an example of kinetic energy?

A) A book resting on a table

B) A stretched rubber band

C) Water flowing in a river

D) A battery powering a light bulb

Correct Option: C

Explanation: Kinetic energy is associated with the motion of objects, such as water flowing in a river. - If the efficiency of a machine is 80%, what percentage of the input energy is wasted?

A) 10%

B) 20%

C) 80%

D) 60%

Correct Option: B

Explanation: Efficiency = (Useful energy output / Total energy input) × 100%. Therefore, wasted energy = 100% – Efficiency = 100% – 80% = 20%. - A force of 50 N is applied to move an object a distance of 5 meters. How much work is done?

A) 250 J

B) 10 J

C) 5 J

D) 100 J

Correct Option: A

Explanation: Work = Force × Distance = 50 N × 5 m = 250 J. - Which of the following statements is true regarding energy?

A) Energy can only be transferred in the form of heat

B) Energy can be created and destroyed

C) Energy can be converted from one form to another with 100% efficiency

D) Energy cannot be converted from one form to another

Correct Option: C

Explanation: Energy conversions are subject to the laws of thermodynamics, which impose limitations on efficiency. - What is the efficiency of a machine that outputs 200 J of work with an input energy of 300 J?

A) 150%

B) 100%

C) 66.7%

D) 75%

Correct Option: C

Explanation: Efficiency = (Output work / Input energy) × 100% = (200/300) × 100% = 66.7%. - Which of the following is a form of renewable energy?

A) Coal

B) Natural gas

C) Solar power

D) Petroleum

Correct Option: C

Explanation: Solar power is derived from sunlight and is considered a renewable energy source. - The gravitational potential energy of an object depends on its:

A) Mass and velocity

B) Mass and height

C) Velocity and height

D) Mass, velocity, and height

Correct Option: B

Explanation: Gravitational potential energy depends on the mass of the object and its height above a reference point. - Which of the following statements about work is true?

A) Work can be negative when the force applied is opposite to the displacement

B) Work is always positive

C) Work is equal to force multiplied by time

D) Work is independent of displacement

Correct Option: A

Explanation: Work can be negative when the force applied is opposite to the displacement, indicating that work is done against the direction of motion. - What is the kinetic energy of a 10 kg object moving at a velocity of 5 m/s?

A) 10 J

B) 50 J

C) 100 J

D) 25 J

Correct Option: B

Explanation: Kinetic energy = J. - Which of the following equations represents gravitational potential energy?

A)

B)

C)

D)

Correct Option: B

Explanation: Gravitational potential energy is calculated using the equation where m is mass, g is acceleration due to gravity, and h is height. - If the efficiency of a machine is 90%, what percentage of the input energy is lost as heat?

A) 90%

B) 10%

C) 20%

D) 100%

Correct Option: B

Explanation: Efficiency = Useful output energy / Total input energy. Therefore, energy lost as heat = 100% – Efficiency = 100% – 90% = 10%. - Which of the following is a unit of power?

A) Joule

B) Newton

C) Watt

D) Kilogram

Correct Option: C

Explanation: Watt is the unit of power, representing one joule of work done per second. - What is the potential energy of a 2 kg object raised 5 meters above the ground?

A) 10 J

B) 25 J

C) 100 J

D) 50 J

Correct Option: D

Explanation: Potential energy = mgh = 2 kg × 10 m/s² × 5 m = 50 J. - A force of 30 N is applied to move an object a distance of 4 meters. How much work is done?

A) 120 J

B) 7.5 J

C) 34 J

D) 10 J

Correct Option: A

Explanation: Work = Force × Distance = 30 N × 4 m = 120 J. - Which of the following statements regarding energy is true?

A) Energy can only be transferred in the form of matter

B) Energy can be created and destroyed

C) Energy can only be converted from potential to kinetic

D) Energy can neither be created nor destroyed

Correct Option: D

Explanation: The law of conservation of energy states that energy cannot be created nor destroyed, only converted from one form to another. - Which of the following is an example of kinetic energy?

A) A compressed spring

B) A moving car

C) A battery

D) A stretched rubber band

Correct Option: B

Explanation: Kinetic energy is associated with the motion of objects, such as a moving car. - If the efficiency of a machine is 75%, what percentage of the input energy is transformed into useful work?

A) 75%

B) 25%

C) 50%

D) 100%

Correct Option: B

Explanation: Efficiency = Useful output energy / Total input energy. Therefore, useful work = Efficiency × Total input energy = 75% of input energy. - What is the power of a machine that does 800 J of work in 20 seconds?

A) 40 W

B) 1600 W

C) 800 W

D) 160 W

Correct Option: A

Explanation: Power = Work / Time = 800 J / 20 s = 40 W. - Which of the following is a non-renewable energy source?

A) Wind

B) Solar

C) Natural gas

D) Biomass

Correct Option: C

Explanation: Natural gas is a fossil fuel and considered a non-renewable energy source. - Which of the following is a form of kinetic energy?

A) Wind energy

B) Gravitational energy

C) Nuclear energy

D) Thermal energy

Correct Option: A

Explanation: Wind energy is a form of kinetic energy associated with the motion of air molecules. - The SI unit of power is:

A) Joule

B) Newton

C) Watt

D) Kilogram

Correct Option: C

Explanation: Watt is the unit of power, named after James Watt. - What is the efficiency of a machine that outputs 400 J of work with an input energy of 500 J?

A) 80%

B) 75%

C) 64%

D) 20%

Correct Option: A

Explanation: Efficiency = (Output work / Input energy) × 100% = (400/500) × 100% = 80%. - Which of the following statements regarding energy is true?

A) Energy can only be converted from potential to kinetic

B) Energy can be created and destroyed

C) Energy can only be transferred in the form of light

D) Energy can neither be created nor destroyed

Correct Option: D

Explanation: The law of conservation of energy states that energy cannot be created nor destroyed, only converted from one form to another. - What is the potential energy of a 3 kg object raised 8 meters above the ground?

A) 12 J

B) 120 J

C) 240 J

D) 200 J

Correct Option: C

Explanation: Potential energy = mgh = 3 kg × 10 m/s² × 8 m = 240 J. - A force of 25 N is applied to move an object a distance of 6 meters. How much work is done?

A) 150 J

B) 4 J

C) 150 N

D) 25 J

Correct Option: A

Explanation: Work = Force × Distance = 25 N × 6 m = 150 J. - Which of the following statements about power is true?

A) Power is a scalar quantity

B) Power is measured in joules

C) Power is the rate of doing work

D) Power is independent of time

Correct Option: C

Explanation: Power is defined as the rate at which work is done or energy is transferred. - What is the kinetic energy of a 5 kg object moving at a velocity of 4 m/s?

A) 20 J

B) 40 J

C) 80 J

D) 100 J

Correct Option: C

Explanation: Kinetic energy = J. - Which of the following is a form of renewable energy?

A) Coal

B) Petroleum

C) Biomass

D) Natural gas

Correct Option: C

Explanation: Biomass energy is derived from organic materials and is considered renewable. - What is the efficiency of a machine that outputs 300 J of work with an input energy of 400 J?

A) 75%

B) 60%

C) 150%

D) 90%

Correct Option: A

Explanation: Efficiency = (Output work / Input energy) × 100% = (300/400) × 100% = 75%. - The efficiency of a machine is always less than:

A) 0%

B) 50%

C) 100%

D) 150%

Correct Option: C

Explanation: Efficiency is a ratio of useful work output to total work input, so it cannot exceed 100%. - Which of the following is a non-renewable energy source?

A) Solar power

B) Wind energy

C) Natural gas

D) Biomass

Correct Option: C

Explanation: Natural gas is a fossil fuel and considered a non-renewable energy source. - What is the power of a machine that does 600 J of work in 10 seconds?

A) 60 W

B) 6 W

C) 100 W

D) 6000 W

Correct Option: A

Explanation: Power = Work / Time = 600 J / 10 s = 60 W. - Which of the following is a unit of energy?

A) Pascal

B) Volt

C) Ampere

D) Joule

Correct Option: D

Explanation: Joule is the unit of energy. - Which of the following is an example of kinetic energy?

A) A stretched rubber band

B) A stationary car

C) A compressed spring

D) A moving car

Correct Option: D

Explanation: Kinetic energy is associated with the motion of objects, such as a moving car. - If the efficiency of a machine is 90%, what percentage of the input energy is transformed into useful work?

A) 10%

B) 90%

C) 100%

D) 80%

Correct Option: B

Explanation: Efficiency = Useful output energy / Total input energy. Therefore, useful work = Efficiency × Total input energy = 90% of input energy. - What is the potential energy of a 4 kg object raised 6 meters above the ground?

A) 48 J

B) 240 J

C) 120 J

D) 144 J

Correct Option: D

Explanation: Potential energy = mgh = 4 kg × 10 m/s² × 6 m = 144 J. - A force of 40 N is applied to move an object a distance of 8 meters. How much work is done?

A) 5 J

B) 40 J

C) 320 J

D) 320 N

Correct Option: C

Explanation: Work = Force × Distance = 40 N × 8 m = 320 J. - Which of the following statements regarding energy is true?

A) Energy can be created but not destroyed

B) Energy can be destroyed but not created

C) Energy can neither be created nor destroyed

D) Energy can be created and destroyed freely

Correct Option: C

Explanation: The law of conservation of energy states that energy cannot be created nor destroyed, only converted from one form to another. - What is the kinetic energy of a 3 kg object moving at a velocity of 6 m/s?

A) 54 J

B) 9 J

C) 108 J

D) 18 J

Correct Option: A

Explanation: Kinetic energy = J. - The efficiency of a machine is always expressed as a:

A) Fraction

B) Decimal

C) Percentage

D) Ratio

Correct Option: C

Explanation: Efficiency is typically expressed as a percentage. - Which of the following is a non-renewable energy source?

A) Wind

B) Solar

C) Nuclear

D) Biomass

Correct Option: C

Explanation: Nuclear energy is derived from radioactive materials and is considered non-renewable. - What is the power of a machine that does 900 J of work in 15 seconds?

A) 60 W

B) 15 W

C) 150 W

D) 9000 W

Correct Option: C

Explanation: Power = Work / Time = 900 J / 15 s = 60 W. - Which of the following is a unit of power?

A) Pascal

B) Volt

C) Watt

D) Ampere

Correct Option: C

Explanation: Watt is the unit of power. - Which of the following is an example of potential energy?

A) A running car

B) A spinning top

C) A stretched rubber band

D) A moving train

Correct Option: C

Explanation: A stretched rubber band has potential energy due to its stretched position. - If the efficiency of a machine is 80%, what percentage of the input energy is lost as heat?

A) 20%

B) 80%

C) 100%

D) 60%

Correct Option: A

Explanation: Efficiency = Useful output energy / Total input energy. Therefore, energy lost as heat = 100% – Efficiency = 100% – 80% = 20%. - Which of the following statements about energy is true?

A) Energy can only be transferred in the form of light

B) Energy can be created and destroyed

C) Energy can neither be created nor destroyed

D) Energy can only be converted from potential to kinetic

Correct Option: C

Explanation: The law of conservation of energy states that energy cannot be created nor destroyed, only converted from one form to another. - What is the kinetic energy of a 6 kg object moving at a velocity of 2 m/s?

A) 12 J

B) 6 J

C) 24 J

D) 18 J

Correct Option: A

Explanation: Kinetic energy = J. - The SI unit of power is:

A) Newton

B) Joule

C) Watt

D) Kilogram

Correct Option: C

Explanation: Watt is the unit of power. - What is the potential energy of a 5 kg object raised 10 meters above the ground?

A) 500 J

B) 1000 J

C) 50 J

D) 200 J

Correct Option: A

Explanation: Potential energy = mgh = 5 kg × 10 m/s² × 10 m = 500 J. - A force of 15 N is applied to move an object a distance of 3 meters. How much work is done?

A) 45 J

B) 5 J

C) 15 J

D) 8 J

Correct Option: A

Explanation: Work = Force × Distance = 15 N × 3 m = 45 J. - Which of the following is a form of renewable energy?

A) Coal

B) Nuclear

C) Wind

D) Natural gas

Correct Option: C

Explanation: Wind energy is considered renewable because it is continuously replenished by nature. - What is the efficiency of a machine that outputs 500 J of work with an input energy of 600 J?

A) 83.3%

B) 80%

C) 125%

D) 70%

Correct Option: A

Explanation: Efficiency = (Output work / Input energy) × 100% = (500/600) × 100% = 83.3%. - Which of the following statements regarding energy conversion is correct?

A) Energy can be created and destroyed

B) Energy can only be converted from kinetic to potential

C) Energy can be converted from one form to another with 100% efficiency

D) Energy can neither be created nor destroyed

Correct Option: D

Explanation: According to the law of conservation of energy, energy cannot be created or destroyed, only converted from one form to another. - What is the kinetic energy of a 4 kg object moving at a velocity of 3 m/s?

A) 6 J

B) 12 J

C) 18 J

D) 36 J

Correct Option: D

Explanation: Kinetic energy = J. - The SI unit of work is the same as the SI unit of:

A) Power

B) Force

C) Energy

D) Momentum

Correct Option: C

Explanation: Work and energy share the same unit, the joule (J). - Which of the following is an example of kinetic energy?

A) A stationary rock at the top of a hill

B) A book on a shelf

C) A stretched rubber band

D) A moving car

Correct Option: D

Explanation: Kinetic energy is associated with the motion of objects, such as a moving car. - If the efficiency of a machine is 70%, what percentage of the input energy is transformed into useful work?

A) 70%

B) 30%

C) 100%

D) 80%

Correct Option: A

Explanation: Efficiency = Useful output energy / Total input energy. Therefore, useful work = Efficiency × Total input energy = 70% of input energy. - What is the power of a machine that does 700 J of work in 14 seconds?

A) 49 W

B) 100 W

C) 50 W D) 70 W

Correct Option: A

Explanation: Power = Work / Time = 700 J / 14 s = 50 W. - Which of the following is a form of potential energy?

A) Sound energy

B) Chemical energy

C) Nuclear energy

D) Gravitational energy

Correct Option: D

Explanation: Gravitational potential energy is associated with an object’s position relative to the Earth’s surface. - The efficiency of a machine is always expressed as a:

A) Fraction

B) Decimal

C) Percentage

D) Ratio

Correct Option: C

Explanation: Efficiency is typically expressed as a percentage. - Which of the following is a non-renewable energy source?

A) Solar

B) Biomass

C) Fossil fuels

D) Wind

Correct Option: C

Explanation: Fossil fuels, such as coal and petroleum, are non-renewable energy sources. - What is the efficiency of a machine that outputs 350 J of work with an input energy of 500 J?

A) 70%

B) 50%

C) 100%

D) 150%

Correct Option: A

Explanation: Efficiency = (Output work / Input energy) × 100% = (350/500) × 100% = 70%. - Which of the following statements about energy is true?

A) Energy can only be transferred in the form of heat

B) Energy can be created and destroyed

C) Energy can only be converted from potential to kinetic

D) Energy can neither be created nor destroyed

Correct Option: D

Explanation: The law of conservation of energy states that energy cannot be created nor destroyed, only converted from one form to another. - What is the potential energy of a 6 kg object raised 7 meters above the ground?

A) 42 J

B) 210 J

C) 294 J

D) 180 J

Correct Option: C

Explanation: Potential energy = mgh = 6 kg × 10 m/s² × 7 m = 294 J. - A force of 35 N is applied to move an object a distance of 5 meters. How much work is done?

A) 70 J

B) 140 J

C) 175 J

D) 5 J

Correct Option: B

Explanation: Work = Force × Distance = 35 N × 5 m = 175 J. - Which of the following is a form of renewable energy?

A) Natural gas

B) Nuclear

C) Wind

D) Coal

Correct Option: C

Explanation: Wind energy is considered renewable because it is continuously replenished by nature. - What is the efficiency of a machine that outputs 450 J of work with an input energy of 600 J?

A) 75%

B) 50%

C) 125%

D) 80%

Correct Option: A

Explanation: Efficiency = (Output work / Input energy) × 100% = (450/600) × 100% = 75%. - What is the power of a machine that does 1000 J of work in 20 seconds?

A) 20 W

B) 50 W

C) 200 W

D) 500 W

Correct Option: C

Explanation: Power = Work / Time = 1000 J / 20 s = 50 W. - Which of the following is a unit of energy?

A) Ampere

B) Pascal

C) Joule

D) Volt

Correct Option: C

Explanation: Joule is the unit of energy. - Which of the following is an example of kinetic energy?

A) A stationary train at a platform

B) A compressed spring

C) A moving bicycle

D) A book on a table

Correct Option: C

Explanation: Kinetic energy is associated with the motion of objects, such as a moving bicycle. - If the efficiency of a machine is 85%, what percentage of the input energy is lost as heat?

A) 15%

B) 85%

C) 100%

D) 75%

Correct Option: A

Explanation: Efficiency = Useful output energy / Total input energy. Therefore, energy lost as heat = 100% – Efficiency = 100% – 85% = 15%. - What is the kinetic energy of a 7 kg object moving at a velocity of 4 m/s?

A) 14 J

B) 112 J

C) 28 J

D) 56 J

Correct Option: D

Explanation: Kinetic energy = J. - The SI unit of power is:

A) Newton

B) Joule

C) Watt

D) Kilogram

Correct Option: C

Explanation: Watt is the unit of power. - What is the potential energy of a 8 kg object raised 9 meters above the ground?

A) 64 J

B) 648 J

C) 720 J

D) 576 J

Correct Option: D

Explanation: Potential energy = mgh = 8 kg × 10 m/s² × 9 m = 720 J. - A force of 25 N is applied to move an object a distance of 4 meters. How much work is done?

A) 29 J

B) 100 J

C) 96 J

D) 10 J

Correct Option: C

Explanation: Work = Force × Distance = 25 N × 4 m = 100 J. - Which of the following is a form of renewable energy?

A) Natural gas

B) Nuclear

C) Wind

D) Coal

Correct Option: C

Explanation: Wind energy is considered renewable because it is continuously replenished by nature. - What is the efficiency of a machine that outputs 550 J of work with an input energy of 750 J?

A) 73.3%

B) 83.3%

C) 66.7%

D) 50%

Correct Option: B

Explanation: Efficiency = (Output work / Input energy) × 100% = (550/750) × 100% = 73.3%. - What is the power of a machine that does 1200 J of work in 30 seconds?

A) 40 W

B) 60 W

C) 120 W

D) 90 W

Correct Option: B

Explanation: Power = Work / Time = 1200 J / 30 s = 40 W. - Which of the following is a unit of energy?

A) Pascal

B) Volt

C) Ampere

D) Joule

Correct Option: D

Explanation: Joule is the unit of energy. - What is the kinetic energy of a 10 kg object moving at a velocity of 5 m/s?

A) 25 J

B) 50 J

C) 100 J

D) 250 J

Correct Option: C

Explanation: Kinetic energy = J. - The SI unit of power is:

A) Newton

B) Joule

C) Watt

D) Kilogram

Correct Option: C

Explanation: Watt is the unit of power. - What is the potential energy of a 2 kg object raised 5 meters above the ground?

A) 10 J

B) 25 J

C) 50 J

D) 100 J

Correct Option: C

Explanation: Potential energy = mgh = 2 kg × 10 m/s² × 5 m = 100 J. - A force of 30 N is applied to move an object a distance of 6 meters. How much work is done?

A) 180 J

B) 36 J

C) 30 J

D) 5 J

Correct Option: A

Explanation: Work = Force × Distance = 30 N × 6 m = 180 J. - Which of the following is a form of kinetic energy?

A) Solar energy

B) Gravitational energy

C) Thermal energy

D) Wind energy

Correct Option: D

Explanation: Wind energy is a form of kinetic energy associated with the motion of air molecules. - If the efficiency of a machine is 90%, what percentage of the input energy is transformed into useful work?

A) 90%

B) 10%

C) 100%

D) 80%

Correct Option: A

Explanation: Efficiency = Useful output energy / Total input energy. Therefore, useful work = Efficiency × Total input energy = 90% of input energy. - What is the efficiency of a machine that outputs 600 J of work with an input energy of 750 J?

A) 80%

B) 75%

C) 64%

D) 20%

Correct Option: B

Explanation: Efficiency = (Output work / Input energy) × 100% = (600/750) × 100% = 75%. - Which of the following is a form of potential energy?

A) Electrical energy

B) Sound energy

C) Nuclear energy

D) Chemical energy

Correct Option: D

Explanation: Chemical energy is a form of potential energy stored in chemical bonds.

## Physics Class 9 MCQs Chapter wise

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