ScienceAges 13-15

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.

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Age band:Ages 10-12 Ages 13-15

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Worksheet StudioPractice pack · Ages 13-15

Percentage energy efficiency

Take your time. Show your thinking.

1. A machine is supplied with 400 J of total energy and transfers 180 J as useful energy output. Calculate its percentage efficiency.
In: 400 J → Useful: 180 J · Wasted: 220 J
2. A machine is supplied with 160 J of total energy and transfers 96 J as useful energy output. Calculate its percentage efficiency.
In: 160 J → Useful: 96 J · Wasted: 64 J
3. A machine is supplied with 480 J of total energy and transfers 96 J as useful energy output. Calculate its percentage efficiency.
In: 480 J → Useful: 96 J · Wasted: 384 J
4. A machine is supplied with 440 J of total energy and transfers 154 J as useful energy output. Calculate its percentage efficiency.
In: 440 J → Useful: 154 J · Wasted: 286 J
5. A machine is supplied with 140 J of total energy and transfers 63 J as useful energy output. Calculate its percentage efficiency.
In: 140 J → Useful: 63 J · Wasted: 77 J
6. A machine is supplied with 380 J of total energy and transfers 304 J as useful energy output. Calculate its percentage efficiency.
In: 380 J → Useful: 304 J · Wasted: 76 J
7. A machine is supplied with 200 J of total energy and transfers 180 J as useful energy output. Calculate its percentage efficiency.
In: 200 J → Useful: 180 J · Wasted: 20 J
8. A machine is supplied with 280 J of total energy and transfers 112 J as useful energy output. Calculate its percentage efficiency.
In: 280 J → Useful: 112 J · Wasted: 168 J
9. A machine is supplied with 140 J of total energy and transfers 112 J as useful energy output. Calculate its percentage efficiency.
In: 140 J → Useful: 112 J · Wasted: 28 J
10. A machine is supplied with 420 J of total energy and transfers 84 J as useful energy output. Calculate its percentage efficiency.
In: 420 J → Useful: 84 J · Wasted: 336 J
11. A machine is supplied with 260 J of total energy and transfers 208 J as useful energy output. Calculate its percentage efficiency.
In: 260 J → Useful: 208 J · Wasted: 52 J
12. A machine is supplied with 420 J of total energy and transfers 357 J as useful energy output. Calculate its percentage efficiency.
In: 420 J → Useful: 357 J · Wasted: 63 J

12 questions · Seed 104731 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 13-15

Percentage energy efficiency

Answers and reasoning. Review before teaching.

1. A machine is supplied with 400 J of total energy and transfers 180 J as useful energy output. Calculate its percentage efficiency.
45%
Efficiency = (useful energy output ÷ total energy input) × 100% = (180 ÷ 400) × 100% = 45%.
2. A machine is supplied with 160 J of total energy and transfers 96 J as useful energy output. Calculate its percentage efficiency.
60%
Efficiency = (useful energy output ÷ total energy input) × 100% = (96 ÷ 160) × 100% = 60%.
3. A machine is supplied with 480 J of total energy and transfers 96 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (96 ÷ 480) × 100% = 20%.
4. A machine is supplied with 440 J of total energy and transfers 154 J as useful energy output. Calculate its percentage efficiency.
35%
Efficiency = (useful energy output ÷ total energy input) × 100% = (154 ÷ 440) × 100% = 35%.
5. A machine is supplied with 140 J of total energy and transfers 63 J as useful energy output. Calculate its percentage efficiency.
45%
Efficiency = (useful energy output ÷ total energy input) × 100% = (63 ÷ 140) × 100% = 45%.
6. A machine is supplied with 380 J of total energy and transfers 304 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (304 ÷ 380) × 100% = 80%.
7. A machine is supplied with 200 J of total energy and transfers 180 J as useful energy output. Calculate its percentage efficiency.
90%
Efficiency = (useful energy output ÷ total energy input) × 100% = (180 ÷ 200) × 100% = 90%.
8. A machine is supplied with 280 J of total energy and transfers 112 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (112 ÷ 280) × 100% = 40%.
9. A machine is supplied with 140 J of total energy and transfers 112 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (112 ÷ 140) × 100% = 80%.
10. A machine is supplied with 420 J of total energy and transfers 84 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (84 ÷ 420) × 100% = 20%.
11. A machine is supplied with 260 J of total energy and transfers 208 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (208 ÷ 260) × 100% = 80%.
12. A machine is supplied with 420 J of total energy and transfers 357 J as useful energy output. Calculate its percentage efficiency.
85%
Efficiency = (useful energy output ÷ total energy input) × 100% = (357 ÷ 420) × 100% = 85%.

12 questions · Seed 104731 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 13-15

Percentage energy efficiency

Take your time. Show your thinking.

1. A machine is supplied with 400 J of total energy and transfers 180 J as useful energy output. Calculate its percentage efficiency.
In: 400 J → Useful: 180 J · Wasted: 220 J
2. A machine is supplied with 160 J of total energy and transfers 96 J as useful energy output. Calculate its percentage efficiency.
In: 160 J → Useful: 96 J · Wasted: 64 J
3. A machine is supplied with 480 J of total energy and transfers 96 J as useful energy output. Calculate its percentage efficiency.
In: 480 J → Useful: 96 J · Wasted: 384 J
4. A machine is supplied with 440 J of total energy and transfers 154 J as useful energy output. Calculate its percentage efficiency.
In: 440 J → Useful: 154 J · Wasted: 286 J
5. A machine is supplied with 140 J of total energy and transfers 63 J as useful energy output. Calculate its percentage efficiency.
In: 140 J → Useful: 63 J · Wasted: 77 J
6. A machine is supplied with 380 J of total energy and transfers 304 J as useful energy output. Calculate its percentage efficiency.
In: 380 J → Useful: 304 J · Wasted: 76 J
7. A machine is supplied with 200 J of total energy and transfers 180 J as useful energy output. Calculate its percentage efficiency.
In: 200 J → Useful: 180 J · Wasted: 20 J
8. A machine is supplied with 280 J of total energy and transfers 112 J as useful energy output. Calculate its percentage efficiency.
In: 280 J → Useful: 112 J · Wasted: 168 J
9. A machine is supplied with 140 J of total energy and transfers 112 J as useful energy output. Calculate its percentage efficiency.
In: 140 J → Useful: 112 J · Wasted: 28 J
10. A machine is supplied with 420 J of total energy and transfers 84 J as useful energy output. Calculate its percentage efficiency.
In: 420 J → Useful: 84 J · Wasted: 336 J
11. A machine is supplied with 260 J of total energy and transfers 208 J as useful energy output. Calculate its percentage efficiency.
In: 260 J → Useful: 208 J · Wasted: 52 J
12. A machine is supplied with 420 J of total energy and transfers 357 J as useful energy output. Calculate its percentage efficiency.
In: 420 J → Useful: 357 J · Wasted: 63 J

12 questions · Seed 104731 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 13-15

Percentage energy efficiency

Answers and reasoning. Review before teaching.

1. A machine is supplied with 400 J of total energy and transfers 180 J as useful energy output. Calculate its percentage efficiency.
45%
Efficiency = (useful energy output ÷ total energy input) × 100% = (180 ÷ 400) × 100% = 45%.
2. A machine is supplied with 160 J of total energy and transfers 96 J as useful energy output. Calculate its percentage efficiency.
60%
Efficiency = (useful energy output ÷ total energy input) × 100% = (96 ÷ 160) × 100% = 60%.
3. A machine is supplied with 480 J of total energy and transfers 96 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (96 ÷ 480) × 100% = 20%.
4. A machine is supplied with 440 J of total energy and transfers 154 J as useful energy output. Calculate its percentage efficiency.
35%
Efficiency = (useful energy output ÷ total energy input) × 100% = (154 ÷ 440) × 100% = 35%.
5. A machine is supplied with 140 J of total energy and transfers 63 J as useful energy output. Calculate its percentage efficiency.
45%
Efficiency = (useful energy output ÷ total energy input) × 100% = (63 ÷ 140) × 100% = 45%.
6. A machine is supplied with 380 J of total energy and transfers 304 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (304 ÷ 380) × 100% = 80%.
7. A machine is supplied with 200 J of total energy and transfers 180 J as useful energy output. Calculate its percentage efficiency.
90%
Efficiency = (useful energy output ÷ total energy input) × 100% = (180 ÷ 200) × 100% = 90%.
8. A machine is supplied with 280 J of total energy and transfers 112 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (112 ÷ 280) × 100% = 40%.
9. A machine is supplied with 140 J of total energy and transfers 112 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (112 ÷ 140) × 100% = 80%.
10. A machine is supplied with 420 J of total energy and transfers 84 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (84 ÷ 420) × 100% = 20%.
11. A machine is supplied with 260 J of total energy and transfers 208 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (208 ÷ 260) × 100% = 80%.
12. A machine is supplied with 420 J of total energy and transfers 357 J as useful energy output. Calculate its percentage efficiency.
85%
Efficiency = (useful energy output ÷ total energy input) × 100% = (357 ÷ 420) × 100% = 85%.

12 questions · Seed 104731 · Age guidance, not curriculum certification