Free Work and Energy MCQs with Answers
748 Work and Energy MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
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Read the Work and Energy notesFree MDCAT chapter notes with key terms748 questions · page 13 of 38
- A. Fv/2
- B. Fv^2/2
- C. Fv^2
- D. Fv
Explanation: Correct Answer: (d) Fv Explanation:Power is the rate of work done, and work is defined as the product of force and displacement in the…
Correct answer: Fv- A. Kinetic energy increases
- B. P.E. increases
- C. P.E. decreases
- D. P.E. does not change
Explanation: Correct Answer: (b) P.E. increases Explanation:Like charges repel each other, meaning a force pushes them apart.As you bring the protons…
Correct answer: P.E. increases- A. Rotatory
- B. Photovoltaic
- C. Galvanic
- D. None
Explanation: Photovoltaic cells convert solar energy directly into electrical energy through the photoelectric effect.Incorrect Options:(a) Rotatory…
Correct answer: Photovoltaic- A. 00
- B. 300
- C. 600
- D. 900
Explanation: Work done (W) by a force acting on an object can be found by the formula:W= F.d.cosθW=25JF= 5Nd= 10mby putting values in the formula, we…
Correct answer: 600- A. 20 J
- B. 26 J
- C. 32 J
- D. zero
Explanation: Work done (W) is given by the dot product of force (F) and displacement (d).
Correct answer: zero- A. 0∘
- B. 45∘
- C. 30∘
- D. 60∘
Explanation: The work done (W) is given by W=F⋅d⋅cos(θ), where F is the force, d is the displacement, and θ is the angle between F and d.
Correct answer: 60∘- A. positive
- B. negative
- C. zero
- D. one
Explanation: When a person lifts a body from the ground, the lifting force acts in the same direction as the displacement (upwards).
Correct answer: positive- A. be at rest
- B. move with the same speed in opposite directions
- C. move with different velocities
- D. move with the same velocity
Explanation: According to the law of conservation of momentum, the total momentum before and after the explosion remains constant.
Correct answer: move with the same speed in opposite directions- A. increases
- B. remains the same
- C. decreases
- D. may increase or decrease
Explanation: When a conservative force does positive work on a body, it imparts energy to the body, increasing its potential energy.Incorrect Options…
Correct answer: increases250. The escape velocity for a body projected from Earth is 11 km/s. If projected at 45∘, it will be
- A. 11 km/s
- B. 44 km/s
- C. 22 km/s
- D. 11 m/s
Explanation: Here's why each option is correct or incorrect:(a) 11 km/s (Correct): This is the correct answer.
Correct answer: 11 km/s- A. 10 J
- B. 90 J
- C. 180 J
- D. 270 J
Explanation: Kinetic energy (K.E.) is given by the formula K.E.=1/2 mv^2, where m is the mass of the body and v is its velocity.
Correct answer: 90 J- A. gR
- B. 2 g/R
- C. g/R
- D. (2gR)^1/2
Explanation: The velocity acquired by a particle falling towards Earth from infinity (assuming no initial velocity) can be calculated using the…
Correct answer: (2gR)^1/2- A. moon
- B. Earth
- C. sun
- D. both (a) and (c)
Explanation: Tides are primarily caused by the gravitational pull of both the moon and the sun.
Correct answer: both (a) and (c)- A. 2 s
- B. 4 s
- C. 8 s
- D. 16 s
Explanation: Power (P) is defined as the rate of doing work. It is given by the formula P=W/t , where W is the work done and t is the time taken.
Correct answer: 8 s- A. 120 J
- B. 30 J
- C. 60 J
- D. 10 J
Explanation: Power (P) is defined as the rate at which work is done or energy is consumed.
Correct answer: 120 J- A. mass of body
- B. mass of planet
- C. density of planet
- D. both (b) and (a)
Explanation: The escape velocity of a body depends on both the mass of the body and the mass of the planet.
Correct answer: both (b) and (a)- A. 30°
- B. 60°
- C. 45°
- D. 90°
Explanation: The work done by a force is given by the formula W=Fdcosθ, where F is the magnitude of the force, d is the displacement, and θ is the…
Correct answer: 60°- A. friction
- B. tension in string
- C. air resistance
- D. all of these
Explanation: Here's why each option is correct:(a) Friction: When objects rub against each other, friction causes energy to be converted into thermal…
Correct answer: all of these- A. 1
- B. 3
- C. 1/3
- D. 9
Explanation: The energy content of food is typically measured in calories or joules.
Correct answer: 9- A. 0 degree
- B. 30 degree
- C. 60 degree
- D. 90 degree
Explanation: Work done (W) by a force acting on an object can be found by the formula:W= F.d.cosθW=25JF= 5Nd= 10mby putting values in the formula, we…
Correct answer: 60 degree