Efficiency

What type of diagram is used to show energy efficiency?

• Bar chart

• Sankey diagram

• Flow chart

• Power diagram

How do we calculate percentage efficiency?

• (useful energy out ÷ total energy in) × 100

• (useful energy in ÷ total energy out) x 100

• (total energy out ÷ useful energy in) x 100

Calculate the efficiency of a bulb with an input energy of 50J, which outputs 40J of thermal energy and 10J of light energy.

• 10%

• 20%

• 25%

• 50%

Which bulb is the most efficient?

• Filament bulb

• LED light

• CFL lamp

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

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.HS-PS3-1

NGSS.HS-PS3-4

What might a title be for this sankey?

• Electrical energy

• Efficient light bulb

• 25 Joules of heat

• Sankey for a good heater.

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%

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.MS-PS3-4

Where does most of the energy go in this transformation.

• Electrical energy

• Light

• Heat

• other

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which of the following is a measure of how well energy is converted from one form to another?

• Power

• Efficiency

• Work

• Energy

Tags

NGSS.HS-PS3-3