Physics P2

Question 1

What process transfers heat through solids?

Answer 1

Conduction

Question 2

What process transfers heat through liquids?

Answer 2

Convection

Question 3

What process transfers heat through empty space?

Answer 3

Radiation

Question 4

What does ‘Thermal conductivity’ mean?

Answer 4

Thermal conductivity is a measure of something’s ability to conduct heat

Question 5

Give an example of a material which has a low thermal conductivity

Answer 5

Plastics

Question 6

What is one similarity between conduction and convection?

Answer 6

They both involve particles gaining kinetic energy

Question 7

What is one difference between conduction and convection?

Answer 7

Only energy is transferred in conduction. In convection the particles move.

Question 8

What kind of heat transfer doesn’t require particles?

Answer 8

Radiation

Question 9

What kind of waves does radiation use to transfer heat?

Answer 9

Infrared waves

Question 10

Describe the process of conduction

Answer 10

Conduction is the process of heat being transmitted to neighbouring particles through collisions.

Question 11

Why does conduction occur in solids but rarely in liquids and gases?

Answer 11

The particles in solids are held close together so there are lots of collisions which pass on the energy. Particles in liquids and gases are further apart so there are less collisions.

Question 12

What type of wave is infrared radiation?

Answer 12

Electromagnetic wave

Question 13

What does infrared radiation transfer and in what form?

Answer 13

It transfers thermal energy in the form of a wave

Question 14

What materials are good at emitting infrared radiation?

Answer 14

Dark, matte materials

Question 15

What materials are good at absorbing infrared radiation?

Answer 15

Light coloured, shiny materials

Question 16

How would infrared radiation affect a black matte tube filled with water?

Answer 16

The infrared radiation would be absorbed by the surface and emitted into the surroundings, meaning the thermal energy is lost from the water and gets colder.

Question 17

How would infrared radiation affect a shiny silver tube filled with water?

Answer 17

The infrared radiation is reflected by the shiny surface back into the liquid. Meaning more thermal energy stays in the water, so it is hotter for longer.

Question 18

What are greenhouse gases and what do they do?

Answer 18

They are gases in the atmosphere that trap heat.

Question 19

What 5 gases contribute the most to the greenhouse effect.

Answer 19

Water vapour (H2O)
Carbon dioxide (CO2)
Nitrous oxide (N2O)
Methane (CH4)
Ozone (O3)

Question 20

Explain the process of the greenhouse effect

Answer 20

The sun’s radiation travels towards the Earth.
Some of the energy is reflected and the rest is absorbed by the Earth’s surface.
The Earth emits heat back into space but greenhouse gases trap it in the atmosphere, causing it to heat up.

Question 21

When a substance is heated, it’s temperature rise depends on what?

Answer 21

The amount of energy supplied to it and the mass of the substance

Question 22

What is the specific heat capacity of a substance?

Answer 22

The energy needed to raise the temperature of 1kg of the substance by 1C

Question 23

What is the formula for calculating the specific heat capacity?

Answer 23

E = m c 0 (the 0 has a line going through the middle)