NEET Physics Power MCQs Set A

a) F × v

b) F/v

c) F/v²

d) F × v²

Answer: F × v

Question: Which of the following must be known in order to determine the power output of an automobile?

a) Work performed and elapsed time of work

b) Force exerted and distance of motion

c) Mass and amount of work performed

d) Final velocity and height

Answer: Work performed and elapsed time of work

Question:  A body of mass m is accelerated uniformly from rest to a speed v in a time T. The instantaneous power delivered to the body as a function of time is given by

a)

b)

c)

d)

Answer:

Question:  A car of mass m starts from rest and accelerates so that the instantaneous power delivered to the car has a constant magnitude p_o. The instantaneous velocity of this car is proportiourl to:

a)

b)

c)

d)

Answer:

Question:  A vehicle is moving with a uniform velocity on a smooth horizontal road, then power delivered by its engine must be

a) zero

b) increasing

c) decreasing

d) uniform

Answer: zero

Question:  How much water, a pump of 2 kW can raise in one minute to a height of 10 m, take g = 10 m/s2?

a) 1200

b) 100

c) 1000

d) 2000

Answer: 1200

Question: The engine of a vehicle delivers constant power. If the vehicle is moving up the inclined plane then, its velocity,

a) must remain constant

b) must increase

c) must decrease

d) may increase, decrease or remain same.

Answer: must remain constant

Question:  A body is moved along a straight line by a machine delivering a constant power. The distance moved by the body in time ‘t’ is proportional to

a) t^3/2

b) t^1/4

c) t^1/2

d) t^3/4

Answer:  t^3/2

Question: A body projected vertically from the earth reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force is greatest

a) at the instant just before the body hits the earth

b) at the highest position of the body

c) it remains constant all through

d) at the instant just after the body is projected

Answer: at the instant just before the body hits the earth

Question: A body of mass 10 kg moves with a velocity v of 2 m/s along a circular path of radius 8 m. The power produced by the body will be

a) zero

b) 49 J/s

c) 98 J/s

d) 10 J/s

Answer: zero

More Questions.....................................

Question:  Johnny and his sister Jane race up a hill. Johnny weighs twice as much as jane and takes twice as long as jane to reach the top . Compared to Jane

a) Johnny did more work and delivered the same amount of power

b) Johnny did more work and delivered more power.

c) Johnny did more work and delivered less power

d) Johnny did less work and johnny delivered less power.

Answer: Johnny did more work and delivered the same amount of power

Question:  A constant power P is applied to a car starting from rest. If v is the velocity of the car at time t, then

a)

b)

c)

d)

Answer:

Question:  If two persons A and B take 2 seconds and 4 seconds respectively to lift an object to the same height h, then the ratio of their powers is

a) 2 : 1

b) 1 : 3

c) 1 : 1

d) 1 : 2

Answer: 2 : 1

Question:  A 10 H.P. motor pumps out water from a well of depth 20 m and fills a water tank of volume 22380 litres at a height of 10 m from the ground. The running time of the motor to fill the empty water tank is (g = 10ms^–2)

a) 15 minutes

b) 5 minutes

c) 10 minutes

d) 20 minutes

Answer: 15 minutes

Question: If a machine gun fires n bullets per second each with kinetic energy K, then the power of the machine gun is

a) nK

b) n²K

c) nK²

d) None of these

Answer:  nK

Question:  An engineer claims to have made an engine delivering 10kW power with fuel consumption of 1 g/s. The calorific value of fuel is 2 kcal/g. This claim is

a) invalid

b) valid

c) depends on engine design

d) dependent on load

Answer: invalid

Question: A force applied by an engine of a train of mass 2.05 × 106 kg changes its velocity from 5m/s to 25 m/s in 5 minutes. The power of the engine is

a) 2.05 MW

b) 6 MW

c) 1.025 MW

d) 5 MW

Answer: 2.05 MW

Question: A 10 m long iron chain of linear mass density 0.8 kg m^–1 is hanging freely from a rigid support. If g = 10 ms^–2, then the power required to left the chain upto the point of support in 10 second

a) 40 W

b) 30 W

c) 20W

d) 10 W

Answer:  40 W

Question: Which of the following must be known in order to determine the power output of an automobile?

a) None of these

b) Force exerted and distance of motion

c) Mass and amount of work performed

d) Final velocity and height

Answer: None of these

Question: The engine of a vehicle delivers constant power. If the vehicle is moving up the inclined plane then, its velocity,

a) must remain constant

b) must increase

c) must decrease

d) may increase, decrease or remain same

Answer: must remain constant