Energy Work and Power Practice Questions
WAEC (West Africa) · WAEC Physics · 141 free MCQs with instant results and detailed explanations.
141
Total
50
Easy
67
Medium
24
Hard
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Sample Questions from Energy Work and Power
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Q1
Easy
If a force of 10 N moves an object 5 meters in the direction of the force, what is the work done?
A.
50 Joules
B.
15 Joules
C.
5 Joules
D.
10 Joules
Show Answer & Explanation
Correct Answer: A
Work is calculated using the formula: Work = Force × Distance. Here, Work = 10 N × 5 m = 50 Joules.
Q2
Easy
Which of the following statements best describes power?
A.
Power is the rate of doing work.
B.
Power is the total work done.
C.
Power is the time taken to do work.
D.
Power is the mass of an object in motion.
Show Answer & Explanation
Correct Answer: A
Power is defined as the rate at which work is done or the amount of work done per unit time, making option A the correct definition.
Q3
Easy
What is the unit of work in the SI system?
A.
Joule
B.
Newton
C.
Watt
D.
Kilowatt
Show Answer & Explanation
Correct Answer: A
Work is defined as the energy transferred when a force is applied over a distance. The SI unit of work is the Joule (J), which is defined as one Newton meter (1 J = 1 N·m).
Q4
Medium
Which of the following statements is true regarding power?
A.
Power is the total energy consumed.
B.
Power is the rate at which work is done.
C.
Power is the amount of energy stored.
D.
Power is the force applied over a distance.
Show Answer & Explanation
Correct Answer: B
Power is defined as the rate at which work is done or energy is transferred. It is calculated using the formula: Power = Work done / Time taken. This makes option B the correct answer.
Q5
Medium
A machine does 300 J of work in 5 seconds. What is the power output of the machine?
A.
15 W
B.
60 W
C.
75 W
D.
100 W
Show Answer & Explanation
Correct Answer: B
Power is calculated by dividing the work done by the time taken. Here, Power = Work / Time = 300 J / 5 s = 60 W.
Q6
Medium
A machine does 5000 J of work in 10 seconds. What is the power output of the machine?
A.
500 W
B.
1000 W
C.
200 W
D.
250 W
Show Answer & Explanation
Correct Answer: B
Power is defined as the amount of work done per unit time. Here, the power can be calculated by dividing the work done (5000 J) by the time taken (10 s), giving 500 W.
Q7
Medium
Which of the following statements about energy conservation is true?
A.
Energy can be created or destroyed.
B.
Energy can only be transformed from one form to another.
C.
Energy is lost when it changes forms.
D.
Kinetic energy does not depend on mass.
Show Answer & Explanation
Correct Answer: B
The law of conservation of energy states that energy cannot be created or destroyed, only transformed from one form to another, making option B correct.
Q8
Hard
A 5 kg block is lifted vertically to a height of 10 m. Calculate the work done against gravity. (Use g = 9.8 m/s²)
A.
490 J
B.
4900 J
C.
980 J
D.
9800 J
Show Answer & Explanation
Correct Answer: A
The work done against gravity is calculated using the formula Work = mgh. Here, m = 5 kg, g = 9.8 m/s², and h = 10 m. Thus, Work = 5 * 9.8 * 10 = 490 J.
Q9
Hard
A 2000 kg car is moving at a speed of 20 m/s. How much kinetic energy does the car have?
A.
400,000 J
B.
200,000 J
C.
800,000 J
D.
1,000,000 J
Show Answer & Explanation
Correct Answer: A
The kinetic energy (KE) is calculated using the formula KE = 0.5 * m * v². For this car, KE = 0.5 * 2000 kg * (20 m/s)² = 0.5 * 2000 * 400 = 400,000 J.
Q10
Hard
A 1500 W electric heater operates for 2 hours. How much energy does it consume in kilowatt-hours?
A.
3 kWh
B.
2 kWh
C.
4 kWh
D.
1 kWh
Show Answer & Explanation
Correct Answer: A
The energy consumed by the heater can be calculated using the formula Energy (kWh) = Power (kW) × Time (h). Here, Power = 1.5 kW and Time = 2 h, so Energy = 1.5 kW × 2 h = 3 kWh.
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Energy Work and Power — WAEC (West Africa) WAEC Physics Practice Questions Online
This page contains 141 practice MCQs for the chapter Energy Work and Power in WAEC (West Africa) WAEC Physics. The questions are organized by difficulty — 50 easy, 67 medium, 24 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.