Free Printable Energy Efficiency

1.

No machine in existence has 100% efficiency due to ____________________.

a)

magic

b)

friction

c)

smoke

d)

input

2.

What is the efficiency of a machine if 55.3 J of work are done on the machine, but only 14.3 J or work are done by the machine?

a)

0.25 Joules

b)

26%

c)

3.86 Joules

d)

386%

3.

Total energy = 200J
Useful energy = 20J

Workout the efficiency of this lightbulb.
$efficiency\ =\ \frac{useful\ enegy}{total\ energy\ in}\ \times100$

a)

100%

b)

80%

c)

40%

d)

10%

4.

Total energy = 350J
Useful energy = 70J

Workout the efficiency of this iphoneX.
$efficiency\ =\ \frac{useful\ energy}{total\ energy\ in}\ \times100\%$

a)

100%

b)

80%

c)

40%

d)

20%

5.

Total energy = 34000J
Useful energy = 340J

Workout the efficiency of this vintage VW Beetle.
$efficiency\ =\ \frac{useful\ energy}{total\ energy\ in}\ \times100\%$

a)

100%

b)

10%

c)

40%

d)

20%

6.

This car needs 8600J of energy to power it. If 5000J is changed into useful energy, how much energy is wasted?

a)

13600J

b)

3600J

c)

5000J

d)

8600J

7.

A car transfers 100 J of chemical energy in order to gain 50 J of kinetic energy. The efficiency of the car is

a)

20%

b)

0.5%

c)

50%

d)

200%

8.

Which of these equations is correct?

a)

$efficiency\ =\ \frac{useful\ energy\ transferred}{total\ energy\ transferred}$

b)

$efficiency\ =\ \frac{total\ energy\ transferred}{useful\ energy\ transferred}$

c)

$energy\ =\ efficiency\ \times100\%$

d)

$efficiency\ =\ \frac{wasted\ energy\ transferred}{total\ energy\ tranferred}$

9.

What is the efficiency of a machine if 55.3 J of work are done on the machine, but only 14.3 J is produced by the 1machine?

a)

0.25 J

b)

26%

c)

386%

d)

3.86 J

10.

What is the efficiency of the machine if the input is 263 J and the output is 142 J?

a)

6.26%

b)

54%

c)

100%

d)

260%

11.

What is the efficiency of a machine that has work input of 40 joules and work output of 35 joules?

a)

87.50%

b)

1200

c)

1.142

d)

114%

12.

What is the work output of a machine that has a work input of 2,800 Joules and an efficiency of 92.3%?

a)

2,690J

b)

92.3J

c)

0.0082J

d)

2,584.4

13.

What is the useful work output of a machine that consumes 2,800 Joules and an efficiency of 40%?

a)

7000 J

b)

2760 J

c)

1120 J

14.

Lucas has been challenged to increase the efficiency of a device he is redesigning. His goal is 90% efficiency. The work input of the device is fixed at 10 joules, so Lucas is trying to improve work output. How many joules of work output should Lucas aim for to attain his goal of 90% efficiency?

a)

9 Joules

b)

900 Joules

c)

0.9 Joules

d)

25

15.

What percent energy is wasted by a machine if the energy input is 262 J and the energy output is 131 J?

a)

5%

b)

50%

c)

100 J

16.

What is the work output of a machine that has a work input of 2,800 Joules and an efficiency of 90%?

a)

25200 J

b)

2520 J

c)

0.0082J

Energy Efficiency

Total questions: 16

Worksheet time: 20mins

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