Efficiency

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

• heat

• chemical energy

• light

• sound waves

Tags

NGSS.MS-PS1-4

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

• False

• True

Energy efficiency of wind turbines is about

• 90%

• 75%

• 40%

• 12%

How much light energy in converted to electrical energy in commercial solar panels?

• 75%

• 60%

• 20%

• 5%

Tags

NGSS.HS-PS3-3

Energy efficiency of incandescent lightbulbs is

• 50%

• 25%

• 15%

• 5%

What is the energy efficiency of hydroelectric dams?

• 90%

• 70%

• 50%

• 29%

Last year some grade 7 students built popsicle-stick bridges. The bridge had a mass of 103g and was able to carry 28.4kg (28,400g). What was its structural efficiency? (You need to round the number up)

• 301

• 245

• 10

• 276

Tags

NGSS.MS-ETS1-3

Efficiency is...

• The percentage of energy that is actually used to do work

• The stuff in the walls that keeps energy in

Leaving lights on in vacant rooms, washing clothes in hot water, and driving alone are examples of what?

• low energy efficiency

• moderate energy efficiency

• high energy efficiency

Tags

NGSS.MS-PS3-3

Which of the following is the correct formula for calculating efficiency?