Free Printable Energy Efficiency Calculations

1.

Energy efficiency =

a)

power x time to boil

b)

final temperature - initial temperature

c)

4.2 x volume of water x change in temperature

d)

useful energy / input energy x 100

2.

Energy efficiency should be expressed as....

a)

Joules

b)

Grams

c)

Watts

d)

%

3.

The efficiency of this light bulb is

a)

40 %

b)

60 %

c)

100 %

d)

1.67 %

e)

0.0167 %

4.

The Russell and Hobbs kettle had a starting temperature of 24 degrees and a final temperature of 100 degrees. The power of this kettle is 2400 watts. It took 84 seconds to boil. 500mL of water was boiled. CALCULATE THE INPUPT ENERGY

(a)

5.

The percent of energy that is used for work

a)

Energy efficiency

b)

Renewable energy

c)

Nonrenewable energy

d)

Combustion

6.

Which of the following is an example of energy efficiency?

a)

A light bulb that converts 90% of electrical energy into light

b)

A car engine that converts 30% of fuel energy into motion

c)

A heater that converts 50% of electrical energy into heat

d)

A solar panel that converts 20% of sunlight into electricity

7.

the percentage of energy put into a system that does useful work.

a)

Energy Conservation

b)

Energy Efficiency

c)

Energy Wattage

d)

Electricity

8.

The percentage of energy put into a system that does useful work is:

a)

energy conservation

b)

renewable energy

c)

energy efficiency

d)

energy conversion

9.

The Russell and Hobbs kettle had a starting temperature of 24 degrees and a final temperature of 100 degrees. The power of this kettle is 2400 watts. It took 84 seconds to boil. 500mL of water was boiled.. CALCULATE THE EFFICIENCY AS A PERCENTAGE

(a)

10.

Energy efficiency is...

a)

How well a device converts input energy into useful energy

b)

Energy that is not used for something useful/ something we want

c)

Energy that is used for something useful

d)

Energy that goes into a device/ process

11.

The wasted energy is....

a)

heat

b)

light

c)

electrical

12.

The Russell and Hobbs kettle had a starting temperature of 24 degrees and a final temperature of 100 degrees. The power of this kettle is 2400 watts. It took 84 seconds to boil. 500mL of water was boiled. CALCULATE THE USEFUL ENERGY

(a)

13.

A car uses 100 J of gasoline. 74 J are turned into mechanical energy. 26 J are transformed into heat. What is the car's efficiency?

a)

74%

b)

26%

c)

.26 %

d)

.74%

14.

An oven uses 400 J of electricity to produce 300 J of heat. How efficient is it?

a)

133 %

b)

75 %

c)

300 %

d)

.75 %

15.

What is the formula for calculating energy efficiency?

a)

$\frac{\text{useful energy output}}{\text{total energy input}} \times 100$

b)

$\frac{\text{total energy input}}{\text{useful energy output}} \times 100$

c)

$\frac{\text{useful energy output}}{\text{total energy input}}$

d)

$\frac{\text{total energy input}}{\text{useful energy output}}$

16.

Which unit is used to express energy efficiency?

a)

Joules

b)

Watts

c)

Grams

d)

%

17.

A machine uses 5000J of energy and outputs 4000J of useful work. What is its energy efficiency?

a)

80%

b)

75%

c)

85%

d)

90%

18.

If a light bulb converts 60% of electrical energy into light, what is its energy efficiency?

a)

60%

b)

40%

c)

100%

d)

80%

19.

What is the main goal of improving energy efficiency in appliances?

a)

To reduce energy waste

b)

To increase energy consumption

c)

To decrease the cost of appliances

d)

To increase the size of appliances

20.

Which of the following represents an energy-efficient process?

a)

A car engine that converts 25% of fuel energy into motion

b)

A heater that converts 70% of electrical energy into heat

c)

A solar panel that converts 15% of sunlight into electricity

d)

A refrigerator that uses 90% of its energy for cooling

21.

How is energy efficiency related to energy conservation?

a)

Energy efficiency is a method to achieve energy conservation

b)

Energy conservation is a method to achieve energy efficiency

c)

They are unrelated concepts

d)

Energy efficiency increases energy consumption

22.

What is the energy efficiency of a device that uses 2000J of energy and outputs 1500J of useful work?

a)

75%

b)

80%

c)

70%

d)

85%

23.

Which of the following is a benefit of energy-efficient buildings?

a)

Reduced energy bills

b)

Increased energy consumption

c)

Higher construction costs

d)

Decreased property value

24.

What is the role of insulation in energy efficiency?

a)

To reduce heat loss

b)

To increase heat loss

c)

To increase energy consumption

d)

To decrease energy efficiency

25.

How does energy efficiency impact the environment?

a)

Reduces carbon emissions

b)

Increases carbon emissions

c)

Has no impact

d)

Increases energy waste

Energy Efficiency Calculations

Total questions: 25

Worksheet time: 25mins

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