Quiz about Energy Efficiency Calculations

Question 1

A car uses 100 J of gasoline. 83 J are turned into mechanical energy. How much should be turned into heat?

Accepted Answer

17 J

Answer

7 J

Answer

83 J

Answer

100 J

Question 2

What does this equation mean? $\frac{useful\ output}{input}\ \times\ 100\%$

Accepted Answer

Efficiency is the fraction of output energy that is useful, compare to how much energy you put in.

Answer

Nothing, it's just math.

Answer

Efficiency compares what useful energy you get out to how much you have to put in.

Answer

Efficiency compares how much you put in to how much you get out, whether it is the type you want or not.

Question 3

A TV uses 200 J of electricity and transforms it into 125 J of sound and light and 75 J of heat. How efficient is it?

Accepted Answer

62.5%

Answer

.625%

Answer

37.5%

Answer

.375%

Question 4

My dog likes to run and bark. If he eats 1000 J of food, and transforms that into 700 J of kinetic energy, 100 J of sound, and 200 J of heat, what is his efficiency?

Accepted Answer

80%

Answer

70%

Answer

20%

Question 5

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

Accepted Answer

54%

Answer

6.26%

Answer

100%

Answer

260%

Question 6

Total energy = 200J
Useful energy = 20J

Workout the efficiency of this lightbulb.
$$efficiency\ =\ \frac{useful\ enegy}{total\ energy\ in}\ imes100$$

Accepted Answer

10%

Answer

100%

Answer

80%

Answer

40%

Question 7

Total energy = 350J
Useful energy = 70J

Workout the efficiency of this iphoneX.
$$efficiency\ =\ \frac{useful\ energy}{total\ energy\ in}\ imes100\%$$

Accepted Answer

20%

Answer

100%

Answer

80%

Answer

40%

Question 8

Total energy = 34000J
Useful energy = 340J

Workout the efficiency of this vintage VW Beetle.
$$efficiency\ =\ \frac{useful\ energy}{total\ energy\ in}\ imes100\%$$

Accepted Answer

10%

Answer

100%

Answer

40%

Answer

20%

Question 9

What is the formula for calculating energy efficiency?

Accepted Answer

$$\frac{useful\ output}{total\ input} imes 100\%$$

Answer

$$\frac{total\ input}{useful\ output} imes 100\%$$

Answer

$$\frac{useful\ output}{total\ input} imes 50\%$$

Answer

$$\frac{total\ input}{useful\ output} imes 50\%$$

Question 10

A light bulb uses 60 J of electrical energy and emits 15 J of light energy. What is its efficiency?

Accepted Answer

25%

Answer

50%

Answer

75%

Answer

100%

Question 11

Which of the following best describes energy efficiency in a real-world context?

Accepted Answer

The ratio of useful energy output to total energy input.

Answer

The total energy input regardless of output.

Answer

The amount of energy lost as heat.

Answer

The total energy output regardless of input.

Question 12

In an experiment, a motor uses 500 J of energy to lift a weight, but only 350 J is used for the actual lifting. What is the efficiency of the motor?

Accepted Answer

70%

Answer

80%

Answer

90%

Answer

60%

Question 13

A refrigerator uses 2000 J of electrical energy and removes 1500 J of heat from its interior. What is the efficiency of the refrigerator?

Accepted Answer

75%

Answer

50%

Answer

25%

Answer

100%

Question 14

If a car engine converts 1000 J of chemical energy from fuel into 300 J of mechanical energy, what is the efficiency of the engine?

Accepted Answer

30%

Answer

70%

Answer

50%

Answer

100%

Question 15

Which of the following statements is true about energy efficiency?

Accepted Answer

It is always less than 100%.

Answer

It can be more than 100%.

Answer

It is always equal to 100%.

Answer

It is not measurable.

Energy Efficiency Calculations

Create a free account and access millions of resources

Similar Resources on Wayground

Popular Resources on Wayground

Discover more resources for Science