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.

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Age band:Ages 10-12 Ages 13-15

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Worksheet StudioPractice pack · Ages 10-12

Percentage energy efficiency

Take your time. Show your thinking.

1. A machine is supplied with 220 J of total energy and transfers 132 J as useful energy output. Calculate its percentage efficiency.
In: 220 J → Useful: 132 J · Wasted: 88 J
2. A machine is supplied with 400 J of total energy and transfers 80 J as useful energy output. Calculate its percentage efficiency.
In: 400 J → Useful: 80 J · Wasted: 320 J
3. A machine is supplied with 380 J of total energy and transfers 171 J as useful energy output. Calculate its percentage efficiency.
In: 380 J → Useful: 171 J · Wasted: 209 J
4. A machine is supplied with 380 J of total energy and transfers 152 J as useful energy output. Calculate its percentage efficiency.
In: 380 J → Useful: 152 J · Wasted: 228 J
5. A machine is supplied with 260 J of total energy and transfers 91 J as useful energy output. Calculate its percentage efficiency.
In: 260 J → Useful: 91 J · Wasted: 169 J
6. 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
7. A machine is supplied with 460 J of total energy and transfers 414 J as useful energy output. Calculate its percentage efficiency.
In: 460 J → Useful: 414 J · Wasted: 46 J
8. A machine is supplied with 360 J of total energy and transfers 288 J as useful energy output. Calculate its percentage efficiency.
In: 360 J → Useful: 288 J · Wasted: 72 J
9. A machine is supplied with 340 J of total energy and transfers 306 J as useful energy output. Calculate its percentage efficiency.
In: 340 J → Useful: 306 J · Wasted: 34 J
10. A machine is supplied with 340 J of total energy and transfers 323 J as useful energy output. Calculate its percentage efficiency.
In: 340 J → Useful: 323 J · Wasted: 17 J
11. A machine is supplied with 20 J of total energy and transfers 10 J as useful energy output. Calculate its percentage efficiency.
In: 20 J → Useful: 10 J · Wasted: 10 J
12. A machine is supplied with 100 J of total energy and transfers 20 J as useful energy output. Calculate its percentage efficiency.
In: 100 J → Useful: 20 J · Wasted: 80 J

12 questions · Seed 104730 · 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 220 J of total energy and transfers 132 J as useful energy output. Calculate its percentage efficiency.
60%
Efficiency = (useful energy output ÷ total energy input) × 100% = (132 ÷ 220) × 100% = 60%.
2. A machine is supplied with 400 J of total energy and transfers 80 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (80 ÷ 400) × 100% = 20%.
3. A machine is supplied with 380 J of total energy and transfers 171 J as useful energy output. Calculate its percentage efficiency.
45%
Efficiency = (useful energy output ÷ total energy input) × 100% = (171 ÷ 380) × 100% = 45%.
4. A machine is supplied with 380 J of total energy and transfers 152 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (152 ÷ 380) × 100% = 40%.
5. A machine is supplied with 260 J of total energy and transfers 91 J as useful energy output. Calculate its percentage efficiency.
35%
Efficiency = (useful energy output ÷ total energy input) × 100% = (91 ÷ 260) × 100% = 35%.
6. 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%.
7. A machine is supplied with 460 J of total energy and transfers 414 J as useful energy output. Calculate its percentage efficiency.
90%
Efficiency = (useful energy output ÷ total energy input) × 100% = (414 ÷ 460) × 100% = 90%.
8. A machine is supplied with 360 J of total energy and transfers 288 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (288 ÷ 360) × 100% = 80%.
9. A machine is supplied with 340 J of total energy and transfers 306 J as useful energy output. Calculate its percentage efficiency.
90%
Efficiency = (useful energy output ÷ total energy input) × 100% = (306 ÷ 340) × 100% = 90%.
10. A machine is supplied with 340 J of total energy and transfers 323 J as useful energy output. Calculate its percentage efficiency.
95%
Efficiency = (useful energy output ÷ total energy input) × 100% = (323 ÷ 340) × 100% = 95%.
11. A machine is supplied with 20 J of total energy and transfers 10 J as useful energy output. Calculate its percentage efficiency.
50%
Efficiency = (useful energy output ÷ total energy input) × 100% = (10 ÷ 20) × 100% = 50%.
12. A machine is supplied with 100 J of total energy and transfers 20 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (20 ÷ 100) × 100% = 20%.

12 questions · Seed 104730 · 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 220 J of total energy and transfers 132 J as useful energy output. Calculate its percentage efficiency.
In: 220 J → Useful: 132 J · Wasted: 88 J
2. A machine is supplied with 400 J of total energy and transfers 80 J as useful energy output. Calculate its percentage efficiency.
In: 400 J → Useful: 80 J · Wasted: 320 J
3. A machine is supplied with 380 J of total energy and transfers 171 J as useful energy output. Calculate its percentage efficiency.
In: 380 J → Useful: 171 J · Wasted: 209 J
4. A machine is supplied with 380 J of total energy and transfers 152 J as useful energy output. Calculate its percentage efficiency.
In: 380 J → Useful: 152 J · Wasted: 228 J
5. A machine is supplied with 260 J of total energy and transfers 91 J as useful energy output. Calculate its percentage efficiency.
In: 260 J → Useful: 91 J · Wasted: 169 J
6. 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
7. A machine is supplied with 460 J of total energy and transfers 414 J as useful energy output. Calculate its percentage efficiency.
In: 460 J → Useful: 414 J · Wasted: 46 J
8. A machine is supplied with 360 J of total energy and transfers 288 J as useful energy output. Calculate its percentage efficiency.
In: 360 J → Useful: 288 J · Wasted: 72 J
9. A machine is supplied with 340 J of total energy and transfers 306 J as useful energy output. Calculate its percentage efficiency.
In: 340 J → Useful: 306 J · Wasted: 34 J
10. A machine is supplied with 340 J of total energy and transfers 323 J as useful energy output. Calculate its percentage efficiency.
In: 340 J → Useful: 323 J · Wasted: 17 J
11. A machine is supplied with 20 J of total energy and transfers 10 J as useful energy output. Calculate its percentage efficiency.
In: 20 J → Useful: 10 J · Wasted: 10 J
12. A machine is supplied with 100 J of total energy and transfers 20 J as useful energy output. Calculate its percentage efficiency.
In: 100 J → Useful: 20 J · Wasted: 80 J

12 questions · Seed 104730 · 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 220 J of total energy and transfers 132 J as useful energy output. Calculate its percentage efficiency.
60%
Efficiency = (useful energy output ÷ total energy input) × 100% = (132 ÷ 220) × 100% = 60%.
2. A machine is supplied with 400 J of total energy and transfers 80 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (80 ÷ 400) × 100% = 20%.
3. A machine is supplied with 380 J of total energy and transfers 171 J as useful energy output. Calculate its percentage efficiency.
45%
Efficiency = (useful energy output ÷ total energy input) × 100% = (171 ÷ 380) × 100% = 45%.
4. A machine is supplied with 380 J of total energy and transfers 152 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (152 ÷ 380) × 100% = 40%.
5. A machine is supplied with 260 J of total energy and transfers 91 J as useful energy output. Calculate its percentage efficiency.
35%
Efficiency = (useful energy output ÷ total energy input) × 100% = (91 ÷ 260) × 100% = 35%.
6. 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%.
7. A machine is supplied with 460 J of total energy and transfers 414 J as useful energy output. Calculate its percentage efficiency.
90%
Efficiency = (useful energy output ÷ total energy input) × 100% = (414 ÷ 460) × 100% = 90%.
8. A machine is supplied with 360 J of total energy and transfers 288 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (288 ÷ 360) × 100% = 80%.
9. A machine is supplied with 340 J of total energy and transfers 306 J as useful energy output. Calculate its percentage efficiency.
90%
Efficiency = (useful energy output ÷ total energy input) × 100% = (306 ÷ 340) × 100% = 90%.
10. A machine is supplied with 340 J of total energy and transfers 323 J as useful energy output. Calculate its percentage efficiency.
95%
Efficiency = (useful energy output ÷ total energy input) × 100% = (323 ÷ 340) × 100% = 95%.
11. A machine is supplied with 20 J of total energy and transfers 10 J as useful energy output. Calculate its percentage efficiency.
50%
Efficiency = (useful energy output ÷ total energy input) × 100% = (10 ÷ 20) × 100% = 50%.
12. A machine is supplied with 100 J of total energy and transfers 20 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (20 ÷ 100) × 100% = 20%.

12 questions · Seed 104730 · Age guidance, not curriculum certification