Energy Efficiency, Sankey Diagram and Power

A kettle uses 100J of electrical energy to produce 7J of sound energy and 93J of thermal energy. How efficient is the kettle?

• 100%

• 7%

• 93%

• 95%

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

• 5%

• 50%

• 55%

• 100%

Tags

NGSS.MS-PS3-5

A hairdryer uses 300J of energy to produce 60J of sound energy and 240J of thermal energy. Calculate it's efficiency.

• 80%

• 90%

• 20%

• 100%

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-5

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%

Tags

NGSS.HS-PS3-3

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

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

If this household wanted to use less energy, where should they first focus their efforts.

• Water heater
• Better lighting
• Unplugging electronics
• More efficient air conditioning

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

Efficiency is calculated by useful energy output divided by total energy input, expressed as a percentage

• False

• True

What is useful energy?

• The total amount of energy put into a system.

• The energy that is lost to heat or other energy types that aren’t useful.

• The energy that is created or destroyed.

• The energy that is used to achieve the desired outcome or do work.

What is efficiency?

• The measurement of how fast someone runs.

• The ability to do work.

• The total amount of energy put into a system.

• A comparison of how much energy is used to do work versus how much is lost or wasted to the environment.

What type of diagram is this?

• Venn Diagram

• Sankey Diagram

• Pie Diagram

• Arrow Diagram