Energy Transfers and Efficiency Quiz

What should students do if they don't understand a part of the video?

• Ask a friend

• Ignore it

• Watch the video again

• Skip to the next section

What type of energy does a fan convert electrical energy into?

• Sound energy

• Light energy

• Kinetic energy

• Thermal energy

Which form of energy is considered wasted in a television?

• Electrical

• Sound

• Light

• Heat

In a car engine, which energy is primarily desired?

• Kinetic energy

• Chemical energy

• Heat energy

• Sound energy

If a device uses 100 joules of energy and outputs 60 joules of light, how much energy is wasted?

• 0 joules

• 100 joules

• 60 joules

• 40 joules

What is the unit of energy used in the exercises?

• Watts

• Joules

• Volts

• Amperes

How is efficiency calculated?

• Useful energy divided by total energy

• Total energy divided by useful energy

• Total energy minus useful energy

• Wasted energy divided by total energy

What does a Sankey diagram represent?

• The speed of energy transfer

• The time taken for energy transfer

• The amount of energy wasted and transformed

• The cost of energy

What is the efficiency of a light bulb that converts 100 joules of electrical energy into 45 joules of light?

• 0.75 or 75%

• 0.45 or 45%

• 0.55 or 55%

• 0.25 or 25%

What is the purpose of multiplying the efficiency by 100?

• To decrease the efficiency

• To increase the efficiency

• To convert it into a decimal

• To convert it into a percentage