Energy

Question 1

How is efficiency calculated?

Answer 1

Efficiency=Useful energy out\Total energy in

You can then multiply by 100 for a percentage.

Question 2

What is the energy transfer for a tablet?

Answer 2

Chemical -> Electrical -> Sound + Light + Thermal

Question 3

What is the energy transfers for a hydroelectric dam?

Answer 3

Gravitational potential -> kinetic -> kinetic -> electrical

Question 4

What does the conservation of energy mean?

Answer 4

Energy can not be created or destroyed.

Only transferred or stored.

Question 5

What are the names of the variables and their units for this equation?
E=Pt

Answer 5

E is Energy in kilowatt hours KWh
P is Power in kilowatts KW
t is time in hours

Question 6

What form of energy is usually considered to be wasted when produced by a device?

Answer 6

Thermal Energy

Question 7

If I have a light bulb that is 75% efficient and input 100J how many joules of light would it give out?

Answer 7

75J