Work and Energy MCQ Questions Class 9 Science Chapter 11
NCERT MCQ Questions for Class 9 Science Chapter 11 Work and Energy. Work and Energy MCQ Questions with Answers from Class 9 Science.
Work and Energy MCQ Questions Class 9 Science Chapter 11
Work and Energy Multiple Choice Questions with Answers Class 9 Science Chapter 11 PDF is available.
1.) Energy is a —-quantity.
a) Scalar
b) Vector
c) Tensor
d) None of these
Answer: a) scalar
2.) If the direction of applied force and displacement is opposite then we say that the work done will be
a) Positive
b) Negative
c) Zero
d) Both a) and b)
3.) If a man hold an object of mass 20 kg at 1.3 m then the value of work done will be
a) 26 J
b) 30 J
c) 20 J
d) 0 J
Answer: d) 0 J
The displacement of particle is zero thus the workdone also zero.
4.) Which of the following is a source of energy?
a) Sun
b) Nuclear reactions
c) Tides
d) All of the above
Answer: d) all of the above
5.) In which of the following examples does the work done not be zero?
a) The stone is rolling on frictionless surface with constant velocity.
b) A small child pushes a truck but truck remains stationary.
c) Moon revolve around earth because of gravitational force exerted by earth.
d) None of the above.
Answer: d) none of the above.
6.) We can derive the formula for kinetic energy is from —
a) Definition of acceleration
b) Second equation of kinematics
c) Third equation of kinematics
d) Equation of potential energy
Answer: c) third equation of kinematics.
7.) A road roller is rolling on inclined road. Identity the energy associated with this.
a) Kinetic energy
b) Potential energy
c) Mechanical energy
d) Light energy.
Answer: a) kinetic energy
In case you are missed :- Previous Chapter MCQ Questions
8.) The bulb glows because of electricity. Identify the energy conversion in this process.
a) Light energy into electrical energy
b) Electrical energy into light energy
c) Chemical energy into heat energy
d) Light energy into heat energy
Answer: b) electrical energy into light energy.
9.) A ball is released from certain height. Which of the following statement is correct about this example?
a) Kinetic energy decreases at each second
b) Potential energy decreases at each second.
c) Total energy decreases at each second.
d) All of the above.
Answer: b) potential energy decreases at each second.
10.) The unit of power is –
a) HP
b) J/S
c) Kilowatt
d) All of the above
Answer: d) All of the above.
11.) The stone of mass 3.5 kg is height of 165 cm. Calculate potential energy contained in that stone.
a) 52.6 J
b) 54.6 J
c) 56.6 J
d) 58.6 J
Answer: c) 56.6 J
Given, height = 165 cm = 1.65 m,
Mass of the stone = 3.5 kg,
As, g = 9.8 m/s²,
We know the formula for calculating potential energy,
Potential energy= mgh
Potential energy= 3.5 × 9.8 × 1.65
Potential energy= 56.6 J
12.) A car of mass 325 kg is moving with 20 m/s. Calculate kinetic energy.
a) 60.kJ
b) 65 KJ
c) 70 KJ
d) 75 KJ
Answer: b) 65 KJ
Given, mass =m= 325 kg,
Velocity= v = 20 m/s,
As we know,
Kinetic energy= ½mv²
Kinetic energy= ½×325 × 20²
Kinetic energy= ½ ×325 × 400
Kinetic energy=65000 J
Kinetic energy= 65 KJ
13.) A bulb of rating 52 watt is on for 2 hours. Calculate energy consumed by the bulb.
a) 374.4 KJ
b) 372.4 KJ
c) 370.4 KJ
d) 368.4 KJ
Answer: a) 372.4 KJ
Given,
Power = 52 watt,
Time = 2 hours = 7200 s,
As we know that,
Power = energy/time
Energy = power × time
Energy = 52 × 7200
Energy = 374400 J.
Energy= 374.4 KJ.
14.) A man do work of 730 J in 20 seconds. Calculate power delivered by the man.
a) 35.5 watt
b) 36.5 watt
c) 37.5 watt
d) 38.5 watt
Answer: b) 36.5 watt
Given, work done = 730 J,
Time = 20 s,
As we know,
Power = work done/time
Power = 730 /20
Power = 36.5 Watt.
15.) A ball is thrown vertically upward. The value of kinetic energy —-
a) Increases at every second
b) Decreases at every second
c) Remains constant.
d) Initially increases and then decreases
Answer: d) Decreases at every second
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