Yr 8 Physics

Question 1

Identify the type of heat transfer:
A room becomes warm after the heater is turned on

Answer 1

Convection

Question 2

How does radiation transfer heat energy?

Answer 2

Heat Waves, spreads outwards to transfer heat

Question 3

Energy flow diagram for releasing a bow and arrow

Answer 3

Elastic potential energy -> kinetic energy -> kinetic energy and gravitational potential energy

Question 4

What state of matter does convection occur in?

Answer 4

Liquids and gases

Question 5

Why can’t you hear heels on carpet?

Answer 5

The sound energy from both the objects cancel each other out. The carpet also absorbs the sound energy.

Question 6

What’s the formula for Gravitational potential energy

Answer 6

GPE= m x g x h
(mass by gravity by height)

Question 7

Convert g to kg

Answer 7

divide by 100

Question 8

Identify the type of heat transfer:
A kettle is turned on and the water is boiled

Answer 8

Convection

Question 9

How do you find kinetic energy?

Answer 9

GPE of point A - GPE of point B

Question 10

Define conduction

Answer 10

Conduction happens when two objects are in contact with each other, or when a heat source is in direct contact with a material

Question 11

Sound energy is a form of what kind of energy?

Answer 11

Kinetic energy

Question 12

What is sound transmission?

Answer 12

the spread of sounds through materials and air

Question 13

Convert j to jk

Answer 13

divide by 1000

Question 14

List some examples of things or objects that use echo-location.

Question 15

Energy flow diagram for a light bulb turning on

Answer 15

Chemical potential energy -> Electrical energy -> Light and heat energy

Question 16

What state of matter does conduction happen in?

Answer 16

Solids

Question 17

Define Insulation

Answer 17

Insulation isa material that resists or blocks the flow of heat energy (opposite of conduction/convection)

Question 18

Contrast heat and sound energy

Question 19

A saucepan on a stovetop is filled with water. Once left for a while, the water begins to boil.

a. Identify the types of heat transfer involved in this situation.

b. Explain why the water is able to heat up and boil.

Answer 19

a. Both conduction and convection

b. Conduction is heating the pot which is then heating the water inside causing it to boil

Question 20

How does sound energy travel?

Answer 20

sound waves

Question 21

What is the Law of Conservation of Energy?

Answer 21

Energy cannot be created or destroyed

Question 22

What’s the formula for energy efficacy?

Answer 22

used energy/total energy x 100