energy and efficiency

Question 1

input energy = useful ________ __________ + energy __________

Answer 1

useful energy transferred + energy wasted

Question 2

efficiency=

Answer 2

useful power out
———————— x 100
total power in

Question 3

machines wasting energy: friction

Answer 3

use lubrication

Question 4

machines wasting energy: air resistance

Answer 4

streamline shapes of moving objects

Question 5

machines wasting energy: electrical resistance

Answer 5

in circuits, use wires with as little electrical resistance as possible

Question 6

machines wasting energy: noise

Answer 6

tighten loose parts

Question 7

chemical

Answer 7

atoms bonding together

Question 8

elastic potential

Answer 8

materials being stretched or squeezed

Question 9

magnetic

Answer 9

magnetic charges moving closer or further apart

Question 10

gravitational potential

Answer 10

moving towards/away from earth’s surface

Question 11

kinetic

Answer 11

moving objects

Question 12

thermal

Answer 12

in hot objects

Question 13

electrostatic

Answer 13

electric charges moving closer/further apart

Question 14

the 4 energy transfers

Answer 14

mechanical
electrical
heating
radiation

Question 15

wasted energy does what?

Answer 15

dissipates into the surroundings

Question 16

how can houses be energy efficient?

Answer 16

• double glazing
• loft insulation
• cavity wall insulation
• carpets and curtains
• draft excluders

Question 17

renewable resources

Answer 17

• sun
• wind
• water
• geothermal

Question 18

finite resources

Answer 18

• fossil fuel:
• coal
• oil
• gas
• nuclear