Heat Transfer

Question 0

Define: Infrared Radiation

Answer 0

Part of the electromagnetic spectrum with a longer wavelength than visible red light. The hotter an object the more infrared it emits.

Question 1

Define: Dark materials

Answer 1

Absorb more infra-red than light materials

Question 2

Define: Shiny materials

Answer 2

Poor absorbers and emitters of infra-red radiation

Question 3

Define: Solid

Answer 3

Particles are in fixed positions and close together. Solids have a fixed volume and keep their shape. Solids cannot flow. Low kinetic energy.

Question 4

Define: Liquid

Answer 4

Particles are not in fixed positions. Liquids can flow and have a fixed volume but can change their shape. More kinetic energy than solids, but less than gases.

Question 5

Define: Gas

Answer 5

Particles are not in fixed positions. Gases can flow and do not have a fixed volume or shape. High kinetic energy.

Question 6

Define: Conduction

Answer 6

Transfer of heat energy through a solid. Metals are good conductors because of free electrons.

Question 7

Define: Convection

Answer 7

Convection currents form in fluids (liquids and gases) due to changes in density. The heated particles spread out lowering the density. The less dense material rises. As it moves away from the heat source it cools, becomes denser and sinks.

Question 8

Define: Radiation

Answer 8

Radiation is the transfer of heat without a medium. It is infra-red radiation, part of the electromagnetic spectrum.

Question 9

Define: Conductor

Answer 9

Conducts electricity. Usually a metal, with lots of free electrons

Question 10

Define: Insulator

Answer 10

Does not conduct electricity

Question 11

Define: Evaporation

Answer 11

When a liquid becomes a gas, it takes energy away from the surface giving a cooling effect.

Question 12

Define: Temperature difference

Answer 12

The greater the temperature difference between an object and its surroundings, the faster the rate of heat energy transfer

Question 13

Define: U-value

Answer 13

Measures how effective a material is as an insulator. The lower the u-value, the better the material is as an insulator.

Question 14

Define: Solar panels

Answer 14

Contain water that is heated by radiation from the sun and used to heat buildings or provide domestic hot water.

Question 15

Define: Specific heat capacity

Answer 15

The amount of energy required to change the temperature of one kilogram of a substance by one degree.

Question 16

Define: Payback time

Answer 16

The time it takes for the savings you make to cover the cost of installing insulation or an energy source.

Question 17

Define: Efficiency

Answer 17

Useful energy out divided by total energy in times 100%

Question 18

Define: Energy types

Answer 18

There are 9: Light, sound, thermal, electrical, kinetic, gravitational potential, chemical, elastic potential, nuclear

Question 19

Define: Power

Answer 19

The amount of energy (J) transferred by a device in one second. The unit is the Watt (W).

Question 20

Define: Kilowatt-hour

Answer 20

This is a unit of energy. It is the amount of energy (kW) transferred per hour.

Question 21

Define: Fossil fuels

Answer 21

Coal, oil and gas. Non-renewable.

Question 22

Define: Nuclear fuel

Answer 22

Energy from nuclear fission of uranium used to generate electricity.

Question 23

Define: Biofuel

Answer 23

Energy from animal/human waste used to generate electricity.

Question 24

Define: Water power

Answer 24

From waves, hydroelectric or tidal

Question 25

Define: Hydroelectric power

Answer 25

Where GPE stored behind a dam is transferred to kinetic energy of water flowing through pipes with turbines in them.

Question 26

Define: Solar cell

Answer 26

Converts the sun’s light energy into electricity

Question 27

Define: Solar panel

Answer 27

Uses the sun’s heat energy to heat water for domestic building heating or hot water.

Question 28

Define: Geothermal energy

Answer 28

Energy from volcanic areas where hot water and steam rise to the surface.

Question 29

Define: Small-scale electricity production

Answer 29

Locally useful production of electricity. Useful in remote areas, but sometimes uneconomical to connect to the National Grid.

Question 30

Define: Carbon capture

Answer 30

Catching and storing of carbon dioxide released in some methods of electricity production. Depleted oil and gas fields are good areas for carbon capture storage.

Question 31

Define: National Grid

Answer 31

System of cables and transformers which distributes electricity

Question 32

Define: Step-up transformer

Answer 32

Increases the voltage and decreases the current in the cables of the National Grid to minimise energy wastage

Question 33

Define: Step-down transformer

Answer 33

Decreases the voltage and increases the current of the electricity supply for business or domestic use