Energy Efficiency Calculations

An oven uses 400 J of electricity to produce 300 J of heat. How efficient is it?

• 133 %

• 75 %

• 300 %

• .75 %

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

A blender uses 1000 J of energy to spin it's blades and make smoothies. What is the input energy?

• Electrical

• Sound

• Heat

• Mechanical

A blender uses 1000 J of energy to spin it's blades and make smoothies. What is the useful output energy?

• Electrical

• Sound

• Heat

• Mechanical

A car uses 100 J of gasoline. 83 J are turned into mechanical energy. How much should be turned into heat?

• 7 J

• 17 J

• 83 J

• 100 J

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

NGSS.HS-PS3-4

A car uses 100 J of gasoline. 74 J are turned into mechanical energy. 26 J are transformed into heat. What is the car's efficiency?

• 74%

• 26%

• .26 %

• .74%

Tags

NGSS.MS-PS3-5

What is the equation for energy efficiency?

An oven uses energy to produce heat, light, and sound. If it produces 400 J of heat, 75 J of light, and 50 J of sound, how much input energy did it have?

• 400 J

• 500 J

• 525 J

• 375 J

Tags

NGSS.MS-PS3-5

Total energy in has to equal

• Total energy out (wasteful + useful)

• Useful energy out

• Useful out - wasteful

A TV uses 200 J of electricity and transforms it into 125 J of sound and light and 75 J of heat. How efficient is it?

• 62.5%

• .625%

• 37.5%

• .375%

Tags

NGSS.MS-PS3-3

My dog likes to run and bark. If he eats 1000 J of food, and transforms that into 700 J of kinetic energy, 100 J of sound, and 200 J of heat, what is his efficiency?

• 80%

• 70%

• 20%

Tags

NGSS.MS-PS3-5