conservation of energy

According to the law of conservation of energy, energy can be created or destroyed.

• True

• False

Identify the energy transfer

• chemical to kinetic

• solar to electrical

• thermal to light

• electrical to light

What units are used to measure energy?

• Watts
• Newtons
• Joules
• kilowatts

What is this diagram called?

• Stankey Diagram

• Sankey Diagram

• Sankay Diagram

• Samkay Diagram

Where does most of the energy go in this transformation.

• Electrical energy
• Light
• Heat
• other

Where does most of the energy go for this transformation.

• heat
• electrical
• light
• joules

What type of device might this Sankey be about?

• A very efficient LED light bulb
• A very inefficient incandescent light bulb
• A coal power plant
• A wind turbine

The energy efficiency shown in this diagram is:

• About 10%.

• About 30%.

• About 60%.

• Impossible to tell.

A washing machine uses 250J of electrical energy to produce 125J of useful energy. How efficient is it?

• 5%

• 50%

• 55%

• 100%

An iPhone charger coverts 75J of electricty in to 50J of charge and 25J of thermal energy. How efficient is the charger?

• 10%

• 100%

• 33%

• 67%