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 440 J of total energy and transfers 176 J as useful energy output. Calculate its percentage efficiency.
In: 440 J → Useful: 176 J · Wasted: 264 J
2. 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
3. A machine is supplied with 60 J of total energy and transfers 18 J as useful energy output. Calculate its percentage efficiency.
In: 60 J → Useful: 18 J · Wasted: 42 J
4. A machine is supplied with 360 J of total energy and transfers 144 J as useful energy output. Calculate its percentage efficiency.
In: 360 J → Useful: 144 J · Wasted: 216 J
5. A machine is supplied with 400 J of total energy and transfers 340 J as useful energy output. Calculate its percentage efficiency.
In: 400 J → Useful: 340 J · Wasted: 60 J
6. A machine is supplied with 460 J of total energy and transfers 345 J as useful energy output. Calculate its percentage efficiency.
In: 460 J → Useful: 345 J · Wasted: 115 J
7. A machine is supplied with 420 J of total energy and transfers 315 J as useful energy output. Calculate its percentage efficiency.
In: 420 J → Useful: 315 J · Wasted: 105 J
8. A machine is supplied with 220 J of total energy and transfers 176 J as useful energy output. Calculate its percentage efficiency.
In: 220 J → Useful: 176 J · Wasted: 44 J
9. 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
10. A machine is supplied with 100 J of total energy and transfers 80 J as useful energy output. Calculate its percentage efficiency.
In: 100 J → Useful: 80 J · Wasted: 20 J
11. A machine is supplied with 160 J of total energy and transfers 48 J as useful energy output. Calculate its percentage efficiency.
In: 160 J → Useful: 48 J · Wasted: 112 J
12. A machine is supplied with 260 J of total energy and transfers 52 J as useful energy output. Calculate its percentage efficiency.
In: 260 J → Useful: 52 J · Wasted: 208 J

12 questions · Seed 104738 · 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 440 J of total energy and transfers 176 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (176 ÷ 440) × 100% = 40%.
2. 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%.
3. A machine is supplied with 60 J of total energy and transfers 18 J as useful energy output. Calculate its percentage efficiency.
30%
Efficiency = (useful energy output ÷ total energy input) × 100% = (18 ÷ 60) × 100% = 30%.
4. A machine is supplied with 360 J of total energy and transfers 144 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (144 ÷ 360) × 100% = 40%.
5. A machine is supplied with 400 J of total energy and transfers 340 J as useful energy output. Calculate its percentage efficiency.
85%
Efficiency = (useful energy output ÷ total energy input) × 100% = (340 ÷ 400) × 100% = 85%.
6. A machine is supplied with 460 J of total energy and transfers 345 J as useful energy output. Calculate its percentage efficiency.
75%
Efficiency = (useful energy output ÷ total energy input) × 100% = (345 ÷ 460) × 100% = 75%.
7. A machine is supplied with 420 J of total energy and transfers 315 J as useful energy output. Calculate its percentage efficiency.
75%
Efficiency = (useful energy output ÷ total energy input) × 100% = (315 ÷ 420) × 100% = 75%.
8. A machine is supplied with 220 J of total energy and transfers 176 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (176 ÷ 220) × 100% = 80%.
9. 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%.
10. A machine is supplied with 100 J of total energy and transfers 80 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (80 ÷ 100) × 100% = 80%.
11. A machine is supplied with 160 J of total energy and transfers 48 J as useful energy output. Calculate its percentage efficiency.
30%
Efficiency = (useful energy output ÷ total energy input) × 100% = (48 ÷ 160) × 100% = 30%.
12. A machine is supplied with 260 J of total energy and transfers 52 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (52 ÷ 260) × 100% = 20%.

12 questions · Seed 104738 · 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 440 J of total energy and transfers 176 J as useful energy output. Calculate its percentage efficiency.
In: 440 J → Useful: 176 J · Wasted: 264 J
2. 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
3. A machine is supplied with 60 J of total energy and transfers 18 J as useful energy output. Calculate its percentage efficiency.
In: 60 J → Useful: 18 J · Wasted: 42 J
4. A machine is supplied with 360 J of total energy and transfers 144 J as useful energy output. Calculate its percentage efficiency.
In: 360 J → Useful: 144 J · Wasted: 216 J
5. A machine is supplied with 400 J of total energy and transfers 340 J as useful energy output. Calculate its percentage efficiency.
In: 400 J → Useful: 340 J · Wasted: 60 J
6. A machine is supplied with 460 J of total energy and transfers 345 J as useful energy output. Calculate its percentage efficiency.
In: 460 J → Useful: 345 J · Wasted: 115 J
7. A machine is supplied with 420 J of total energy and transfers 315 J as useful energy output. Calculate its percentage efficiency.
In: 420 J → Useful: 315 J · Wasted: 105 J
8. A machine is supplied with 220 J of total energy and transfers 176 J as useful energy output. Calculate its percentage efficiency.
In: 220 J → Useful: 176 J · Wasted: 44 J
9. 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
10. A machine is supplied with 100 J of total energy and transfers 80 J as useful energy output. Calculate its percentage efficiency.
In: 100 J → Useful: 80 J · Wasted: 20 J
11. A machine is supplied with 160 J of total energy and transfers 48 J as useful energy output. Calculate its percentage efficiency.
In: 160 J → Useful: 48 J · Wasted: 112 J
12. A machine is supplied with 260 J of total energy and transfers 52 J as useful energy output. Calculate its percentage efficiency.
In: 260 J → Useful: 52 J · Wasted: 208 J

12 questions · Seed 104738 · 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 440 J of total energy and transfers 176 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (176 ÷ 440) × 100% = 40%.
2. 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%.
3. A machine is supplied with 60 J of total energy and transfers 18 J as useful energy output. Calculate its percentage efficiency.
30%
Efficiency = (useful energy output ÷ total energy input) × 100% = (18 ÷ 60) × 100% = 30%.
4. A machine is supplied with 360 J of total energy and transfers 144 J as useful energy output. Calculate its percentage efficiency.
40%
Efficiency = (useful energy output ÷ total energy input) × 100% = (144 ÷ 360) × 100% = 40%.
5. A machine is supplied with 400 J of total energy and transfers 340 J as useful energy output. Calculate its percentage efficiency.
85%
Efficiency = (useful energy output ÷ total energy input) × 100% = (340 ÷ 400) × 100% = 85%.
6. A machine is supplied with 460 J of total energy and transfers 345 J as useful energy output. Calculate its percentage efficiency.
75%
Efficiency = (useful energy output ÷ total energy input) × 100% = (345 ÷ 460) × 100% = 75%.
7. A machine is supplied with 420 J of total energy and transfers 315 J as useful energy output. Calculate its percentage efficiency.
75%
Efficiency = (useful energy output ÷ total energy input) × 100% = (315 ÷ 420) × 100% = 75%.
8. A machine is supplied with 220 J of total energy and transfers 176 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (176 ÷ 220) × 100% = 80%.
9. 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%.
10. A machine is supplied with 100 J of total energy and transfers 80 J as useful energy output. Calculate its percentage efficiency.
80%
Efficiency = (useful energy output ÷ total energy input) × 100% = (80 ÷ 100) × 100% = 80%.
11. A machine is supplied with 160 J of total energy and transfers 48 J as useful energy output. Calculate its percentage efficiency.
30%
Efficiency = (useful energy output ÷ total energy input) × 100% = (48 ÷ 160) × 100% = 30%.
12. A machine is supplied with 260 J of total energy and transfers 52 J as useful energy output. Calculate its percentage efficiency.
20%
Efficiency = (useful energy output ÷ total energy input) × 100% = (52 ÷ 260) × 100% = 20%.

12 questions · Seed 104738 · Age guidance, not curriculum certification