Sankey Diagrams and Energy Efficiency

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

The law of energy conservation says the total energy before the change _______ the total energy after it

• is less than
• is more than
• affects
• equals

Tags

NGSS.HS-PS3-2

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

• False

• True

What is an energy transfer?

• Dancing 
• Movement of energy
• Movement of energy from one store to another
• something moving

In energy transformations, "wasted energy" usually takes what form?

• heat
• chemical energy
• light
• sound waves

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-3