Extra 40 MCQs of chapter:11 Work and Energy – Class 9 Science (CBSE):-
When is work said to be done?
a) When force is applied but there is no displacement
b) When force and displacement are in opposite directions
c) When force and displacement are in the same direction
d) When force is applied but displacement is zero
Ans:
c) When force and displacement are in the same direction
What is the SI unit of work?
a) Newton
b) Joule
c) Watt
d) Pascal
Ans:
b) Joule
Work done is said to be positive when:
a) Displacement is in the direction of force
b) Displacement is opposite to the force
c) No displacement occurs
d) Force and displacement are perpendicular
Ans:
a) Displacement is in the direction of force
If an object is moving in a circular path at constant speed, the work done by the centripetal force is:
a) Positive
b) Negative
c) Zero
d) Infinite
Ans:
c) Zero
When force and displacement are perpendicular, the work done is:
a) Maximum
b) Minimum
c) Zero
d) Infinite
Ans:
c) Zero
A porter carrying a suitcase on his head and walking horizontally does:
a) Positive work
b) Negative work
c) No work
d) Infinite work
Ans:
c) No work
A ball falling freely under gravity does:
a) Positive work
b) Negative work
c) Zero work
d) Variable work
Ans:
a) Positive work
The unit of force is:
a) Newton
b) Joule
c) Pascal
d) Watt
Ans:
a) Newton
A coolie lifting a bag and putting it on his head does work against:
a) Air resistance
b) Gravity
c) Friction
d) Centripetal force
Ans:
b) Gravity
What is the SI unit of energy?
a) Joule
b) Watt
c) Newton
d) Pascal
Ans:
a) Joule
Energy possessed by a body due to its motion is called:
a) Potential energy
b) Kinetic energy
c) Mechanical energy
d) Heat energy
Ans:
b) Kinetic energy
What happens to kinetic energy if the speed is doubled?
a) It remains the same
b) It doubles
c) It becomes four times
d) It becomes half
Ans:
c) It becomes four times
What is potential energy?
a) Energy due to motion
b) Energy due to shape
c) Energy due to position
d) Energy due to heat
Ans:
c) Energy due to position
What type of energy is stored in a stretched bow?
a) Kinetic energy
b) Potential energy
c) Chemical energy
d) Nuclear energy
Ans:
b) Potential energy
Energy stored in food is an example of:
a) Chemical energy
b) Nuclear energy
c) Mechanical energy
d) Electrical energy
Ans:
a) Chemical energy
The sum of kinetic and potential energy is called:
a) Electrical energy
b) Solar energy
c) Mechanical energy
d) Heat energy
Ans:
c) Mechanical energy
Energy can neither be created nor destroyed. This is the:
a) Law of work
b) Law of conservation of energy
c) Law of energy loss
d) Law of gravity
Ans:
b) Law of conservation of energy
Work done on an object is equal to the:
a) Change in velocity
b) Change in acceleration
c) Change in energy
d) Change in mass
Ans:
c) Change in energy
The rate at which work is done is called:
a) Energy
b) Power
c) Force
d) Momentum
Ans:
b) Power
The SI unit of power is:
a) Joule
b) Watt
c) Newton
d) Pascal
Ans:
b) Watt
The formula for power is:
a) P=
WtP
= \frac{W}{
t}P
=
tW
b) P=
WtP
=
WtP
=
Wt
c) P=
W+tP
= W +
tP
=
W+t
d) P=W−
tP
= W -
tP
=W−t
Ans:
a) P=
WtP
= \frac{W}{t}P=
tW
The commercial unit of energy is:
a) Joule
b) Kilowatt-hour
c) Newton
d) Watt
Ans:
b) Kilowatt-hour
One kilowatt-hour is equal to:
a) 1000 J
b) 3600 J
c) 3.6×106J3.6 \times 10^6 J3.6×106J
d) 3.6×103J3.6 \times 10^3 J3.6×103J
Ans:
c) 3.6×106J3.6 \times 10^6 J3.6×106J
A person climbing stairs does work against:
a) Friction
b) Gravity
c) Air resistance
d) Magnetism
Ans:
b) Gravity
Power is said to be 1 watt when:
a) 1 J work is done in 1 sec
b) 10 J work is done in 1 sec
c) 1 J work is done in 10 sec
d) 1 W work is done in 1 sec
Ans:
a) 1 J work is done in 1 sec
Work done depends on:
a) Force and displacement
b) Force and velocity
c) Mass and acceleration
d) Mass and distance
Ans:
a) Force and displacement
The rate of doing work is also called:
a) Energy
b) Power
c) Force
d) Pressure
Ans:
b) Power
Which of the following has the highest kinetic energy?
a) A moving bullet
b) A moving truck
c) A moving bicycle
d) A moving train
Ans:
d) A moving train
A stretched rubber band possesses:
a) Kinetic energy
b) Potential energy
c) Electrical energy
d) Sound energy
Ans:
b) Potential energy
The energy possessed by water stored in a dam is:
a) Kinetic energy
b) Chemical energy
c) Potential energy
d) Electrical energy
Ans:
c) Potential energy
The energy obtained from the Sun is called:
a) Chemical energy
b) Mechanical energy
c) Solar energy
d) Electrical energy
Ans:
c) Solar energy
Work is said to be negative when:
a) Force and displacement are in the same direction
b) Force and displacement are perpendicular
c) Force is opposite to displacement
d) Force is zero
Ans:
c) Force is opposite to displacement
The kinetic energy of a body of mass 2 kg moving with a velocity of 3 m/s is:
a) 3 J
b) 6 J
c) 9 J
d) 18 J
Ans:
c) 9 J
(KE = 1/2 × m × v² = 1/2 × 2 × 3² = 9 J)
A 60 W bulb consumes how much energy in 1 hour?
a) 60 J
b) 3600 J
c) 216000 J
d) 60000 J
Ans:
c) 216000 J
(Energy = Power × Time = 60 W × 3600 s = 216000 J)
The kinetic energy of an object becomes four times if:
a) Its mass is doubled
b) Its velocity is doubled
c) Its mass is halved
d) Its velocity is halved
Ans:
b) Its velocity is doubled
What type of energy transformation takes place in a ceiling fan?
a) Electrical → Mechanical
b) Electrical → Chemical
c) Mechanical → Electrical
d) Potential → Kinetic
Ans:
a) Electrical → Mechanical
Which of the following sources of energy is renewable?
a) Coal
b) Petrol
c) Wind
d) Natural gas
Ans:
c) Wind
