Thermal Energy

Question 1

Conduction is the …

Answer 1

Transfer of heat in solids

Question 2

Examples of Good Thermal Conductors :

Answer 2

Copper
Iron
Metal

Question 3

Examples of Poor Conductors :

Answer 3

Wood
Rubber
Plastic

Question 4

Trapped air is a…

Answer 4

Cheap and effective insulator

Question 5

Hoe does temperature affect the motion of particles in a solid?

Answer 5

When an object is heated the particles’ motion increases, as the particles are more energetic

Question 6

Radiation =

Answer 6

Transfer of thermal energy via infrared waves

Question 7

Hotter objects emit …

Answer 7

More radiation

Question 8

What affects the amount of infrared radiation emitted and absorber by a material?

Answer 8

Different colours and different finishes

Fastest) matt black, glossy black, matt silver, glossy sliver (slowest

Question 9

Various ways to insulate a house?

Answer 9

• Wall cavity filled with insulator
• Double-glazed windows
• Curtains reduce radiation
• Carpets with underlay
• Loft and Roof insulation
• Porch keeps in warm air
• Draught excluders on doors and windows

Question 10

Convection is the …

Answer 10

Transfer of thermal energy in fluids

Question 11

How does temperature affect the movement of particles in fluids?

Answer 11

The particles move faster because when the particles are heated up they tend to move faster and don’t move in large groups, as they travel faster in small groups/separate.

Question 12

Conduction in Solids:

Answer 12

The electrons in a piece of metal can leave their atoms and move about in the metal as free electrons. The part of the metal atoms left behind are now positively charged metal ions.

Question 13

Payback time (years) =

Answer 13

Cost of installation (£) / Savings per year in cost (£)

Question 14

Conduction in Non-metals

Answer 14

When particles with lots of energy in a liquid or gas move and take the place of particle with less heat energy

Question 15

How does density and number of delocalised atoms effect the conductivity of a metal:

Answer 15

The denser the object, the more free-electrons, the better the conductivity

Question 16

How is the roll of convection current formed?

Answer 16

Liquids and gases expand when they are heated. This is because the particles in liquids and gases move faster when they are heated than when they are cold.

As a result, the particles take up more volume. This is because, the gap between the particles widens, while the particles themselves stay the same size.

The liquid or gas in hot areas is less dense than the liquid or gas in cold areas. The denser cold liquid or gas falls into the warm areas.

In this way, convection currents that transfer heat from place to place are set up

Question 17

Wall cavity filled with insulator :

Answer 17

Conduction

Question 18

Double window glazing :

Answer 18

Conduction

Question 19

Curtains :

Answer 19

Radiation

Question 20

Carpets with underlay :

Answer 20

Conduction

Question 21

Porch keeps warm air :

Answer 21

Convection

Question 22

Loft and roof insulation :

Answer 22

Conduction

Question 23

Draught excluders on doors and windows :

Answer 23

Convection