ScienceAges 10-12

Percentage energy efficiency

Calculate the percentage efficiency of a device from useful energy output and total energy input. Review suitability for your learners before teaching.

New variation Try interactive challenge Browse templates

Age band:Ages 10-12 Ages 13-15

Choose “Save as PDF” to keep a copy. Use your browser’s paper setting for A4 or Letter.

Worksheet StudioPractice pack · Ages 10-12

Percentage energy efficiency

Take your time. Show your thinking.

1. A machine is supplied with 460 J of total energy and transfers 184 J as useful energy output. Calculate its percentage efficiency.
In: 460 J → Useful: 184 J · Wasted: 276 J
2. A machine is supplied with 40 J of total energy and transfers 38 J as useful energy output. Calculate its percentage efficiency.
In: 40 J → Useful: 38 J · Wasted: 2 J
3. A machine is supplied with 180 J of total energy and transfers 108 J as useful energy output. Calculate its percentage efficiency.
In: 180 J → Useful: 108 J · Wasted: 72 J
4. A machine is supplied with 200 J of total energy and transfers 190 J as useful energy output. Calculate its percentage efficiency.
In: 200 J → Useful: 190 J · Wasted: 10 J
5. A machine is supplied with 440 J of total energy and transfers 132 J as useful energy output. Calculate its percentage efficiency.
In: 440 J → Useful: 132 J · Wasted: 308 J
6. A machine is supplied with 160 J of total energy and transfers 64 J as useful energy output. Calculate its percentage efficiency.
In: 160 J → Useful: 64 J · Wasted: 96 J
7. A machine is supplied with 40 J of total energy and transfers 20 J as useful energy output. Calculate its percentage efficiency.
In: 40 J → Useful: 20 J · Wasted: 20 J
8. A machine is supplied with 40 J of total energy and transfers 16 J as useful energy output. Calculate its percentage efficiency.
In: 40 J → Useful: 16 J · Wasted: 24 J
9. A machine is supplied with 20 J of total energy and transfers 6 J as useful energy output. Calculate its percentage efficiency.
In: 20 J → Useful: 6 J · Wasted: 14 J
10. A machine is supplied with 400 J of total energy and transfers 60 J as useful energy output. Calculate its percentage efficiency.
In: 400 J → Useful: 60 J · Wasted: 340 J
11. A machine is supplied with 500 J of total energy and transfers 100 J as useful energy output. Calculate its percentage efficiency.
In: 500 J → Useful: 100 J · Wasted: 400 J
12. A machine is supplied with 500 J of total energy and transfers 400 J as useful energy output. Calculate its percentage efficiency.
In: 500 J → Useful: 400 J · Wasted: 100 J

12 questions · Seed 104743 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 10-12

Percentage energy efficiency

Answers and reasoning. Review before teaching.

1. A machine is supplied with 460 J of total energy and transfers 184 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (184 ÷ 460) × 100% = 40%.
2. A machine is supplied with 40 J of total energy and transfers 38 J as useful energy output. Calculate its percentage efficiency.
95%
Efficiency = (useful energy output ÷ total energy input) × 100% = (38 ÷ 40) × 100% = 95%.
3. A machine is supplied with 180 J of total energy and transfers 108 J as useful energy output. Calculate its percentage efficiency.
60%
Efficiency = (useful energy output ÷ total energy input) × 100% = (108 ÷ 180) × 100% = 60%.
4. A machine is supplied with 200 J of total energy and transfers 190 J as useful energy output. Calculate its percentage efficiency.
95%
Efficiency = (useful energy output ÷ total energy input) × 100% = (190 ÷ 200) × 100% = 95%.
5. A machine is supplied with 440 J of total energy and transfers 132 J as useful energy output. Calculate its percentage efficiency.
30%
Efficiency = (useful energy output ÷ total energy input) × 100% = (132 ÷ 440) × 100% = 30%.
6. A machine is supplied with 160 J of total energy and transfers 64 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (64 ÷ 160) × 100% = 40%.
7. A machine is supplied with 40 J of total energy and transfers 20 J as useful energy output. Calculate its percentage efficiency.
50%
Efficiency = (useful energy output ÷ total energy input) × 100% = (20 ÷ 40) × 100% = 50%.
8. A machine is supplied with 40 J of total energy and transfers 16 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (16 ÷ 40) × 100% = 40%.
9. A machine is supplied with 20 J of total energy and transfers 6 J as useful energy output. Calculate its percentage efficiency.
30%
Efficiency = (useful energy output ÷ total energy input) × 100% = (6 ÷ 20) × 100% = 30%.
10. A machine is supplied with 400 J of total energy and transfers 60 J as useful energy output. Calculate its percentage efficiency.
15%
Efficiency = (useful energy output ÷ total energy input) × 100% = (60 ÷ 400) × 100% = 15%.
11. A machine is supplied with 500 J of total energy and transfers 100 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (100 ÷ 500) × 100% = 20%.
12. A machine is supplied with 500 J of total energy and transfers 400 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (400 ÷ 500) × 100% = 80%.

12 questions · Seed 104743 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 10-12

Percentage energy efficiency

Take your time. Show your thinking.

1. A machine is supplied with 460 J of total energy and transfers 184 J as useful energy output. Calculate its percentage efficiency.
In: 460 J → Useful: 184 J · Wasted: 276 J
2. A machine is supplied with 40 J of total energy and transfers 38 J as useful energy output. Calculate its percentage efficiency.
In: 40 J → Useful: 38 J · Wasted: 2 J
3. A machine is supplied with 180 J of total energy and transfers 108 J as useful energy output. Calculate its percentage efficiency.
In: 180 J → Useful: 108 J · Wasted: 72 J
4. A machine is supplied with 200 J of total energy and transfers 190 J as useful energy output. Calculate its percentage efficiency.
In: 200 J → Useful: 190 J · Wasted: 10 J
5. A machine is supplied with 440 J of total energy and transfers 132 J as useful energy output. Calculate its percentage efficiency.
In: 440 J → Useful: 132 J · Wasted: 308 J
6. A machine is supplied with 160 J of total energy and transfers 64 J as useful energy output. Calculate its percentage efficiency.
In: 160 J → Useful: 64 J · Wasted: 96 J
7. A machine is supplied with 40 J of total energy and transfers 20 J as useful energy output. Calculate its percentage efficiency.
In: 40 J → Useful: 20 J · Wasted: 20 J
8. A machine is supplied with 40 J of total energy and transfers 16 J as useful energy output. Calculate its percentage efficiency.
In: 40 J → Useful: 16 J · Wasted: 24 J
9. A machine is supplied with 20 J of total energy and transfers 6 J as useful energy output. Calculate its percentage efficiency.
In: 20 J → Useful: 6 J · Wasted: 14 J
10. A machine is supplied with 400 J of total energy and transfers 60 J as useful energy output. Calculate its percentage efficiency.
In: 400 J → Useful: 60 J · Wasted: 340 J
11. A machine is supplied with 500 J of total energy and transfers 100 J as useful energy output. Calculate its percentage efficiency.
In: 500 J → Useful: 100 J · Wasted: 400 J
12. A machine is supplied with 500 J of total energy and transfers 400 J as useful energy output. Calculate its percentage efficiency.
In: 500 J → Useful: 400 J · Wasted: 100 J

12 questions · Seed 104743 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 10-12

Percentage energy efficiency

Answers and reasoning. Review before teaching.

1. A machine is supplied with 460 J of total energy and transfers 184 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (184 ÷ 460) × 100% = 40%.
2. A machine is supplied with 40 J of total energy and transfers 38 J as useful energy output. Calculate its percentage efficiency.
95%
Efficiency = (useful energy output ÷ total energy input) × 100% = (38 ÷ 40) × 100% = 95%.
3. A machine is supplied with 180 J of total energy and transfers 108 J as useful energy output. Calculate its percentage efficiency.
60%
Efficiency = (useful energy output ÷ total energy input) × 100% = (108 ÷ 180) × 100% = 60%.
4. A machine is supplied with 200 J of total energy and transfers 190 J as useful energy output. Calculate its percentage efficiency.
95%
Efficiency = (useful energy output ÷ total energy input) × 100% = (190 ÷ 200) × 100% = 95%.
5. A machine is supplied with 440 J of total energy and transfers 132 J as useful energy output. Calculate its percentage efficiency.
30%
Efficiency = (useful energy output ÷ total energy input) × 100% = (132 ÷ 440) × 100% = 30%.
6. A machine is supplied with 160 J of total energy and transfers 64 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (64 ÷ 160) × 100% = 40%.
7. A machine is supplied with 40 J of total energy and transfers 20 J as useful energy output. Calculate its percentage efficiency.
50%
Efficiency = (useful energy output ÷ total energy input) × 100% = (20 ÷ 40) × 100% = 50%.
8. A machine is supplied with 40 J of total energy and transfers 16 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (16 ÷ 40) × 100% = 40%.
9. A machine is supplied with 20 J of total energy and transfers 6 J as useful energy output. Calculate its percentage efficiency.
30%
Efficiency = (useful energy output ÷ total energy input) × 100% = (6 ÷ 20) × 100% = 30%.
10. A machine is supplied with 400 J of total energy and transfers 60 J as useful energy output. Calculate its percentage efficiency.
15%
Efficiency = (useful energy output ÷ total energy input) × 100% = (60 ÷ 400) × 100% = 15%.
11. A machine is supplied with 500 J of total energy and transfers 100 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (100 ÷ 500) × 100% = 20%.
12. A machine is supplied with 500 J of total energy and transfers 400 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (400 ÷ 500) × 100% = 80%.

12 questions · Seed 104743 · Age guidance, not curriculum certification