Efficiency and Power

What is the unit for energy?

• J

• W

• kg

• mL

What does J stand for?

• Joules

• Jellies

• Jangs

• Julls

What is missing from this formula to calculate efficiency of an appliance?

• x 100

• + 100

• - 100

• / 100

What is waste energy usually released as?

• Heat energy

• Kinetic energy

• Chemical energy

• Electrical energy

What is the useful energy output for a hairdryer that has an input energy of 9J and waste output energy of 5J?

• 4J

• 14J

• 45J

• 9J

What is the definition of Power?

• The rate at which energy is used

• How much heat energy is released

• How strong a person is

• How long you leave the lights on for

What are the units for measuring Power?

• W

• J

• kg

• mL

What does W stand for?

• Watts

• What

• Wozzas

• Whoops

How much is 1 W?

• 1 J per second

• 10 J per second

• 1 J per minute

• 10 J per minute

How much electrical energy does a 20 W electric light use every second to stay lit?

• 20 J

• 200 J

• 1 J

• 10 J