IGCSE Physics - Energy resources and energy transfers Units

2. Kilowatt-hour (kWh)

A unit of energy commonly used for measuring electricity consumption, equal to the energy consumed by a 1 kW appliance running for one hour.

4. Kilowatt (kW)

A unit of power equal to 1000 watts.

1. Joule (J)

The SI unit of energy, defined as the work done when a force of one newton is applied through a distance of one metre.

3. Watt (W)

The SI unit of power, defined as the rate of energy transfer or work done per second.

12. Specific heat capacity

The amount of heat energy required to raise the temperature of 1 kilogram of a substance by 1 degree Celsius.

11. Energy

The capacity to do work or transfer heat, measured in joules.

6. Kinetic energy

The energy possessed by a moving object due to its motion, equal to one-half of the mass multiplied by the square of the velocity.

5. Gravitational potential energy

The energy stored in an object due to its position in a gravitational field, equal to the product of the mass, gravitational field strength, and height.

8. Work done

The energy transferred when a force acts on an object and causes it to move through a distance, equal to the product of the force and the distance moved in the direction of the force.

7. Thermal energy

The internal energy of a substance due to the motion of its particles, measured in joules.

10. Power

The rate at which energy is transferred or work is done, equal to the energy transferred or work done divided by the time taken.

9. Efficiency

The ratio of useful energy output to total energy input, expressed as a percentage.

14. Convection

The transfer of thermal energy through a fluid (liquid or gas) by the movement of particles.

13. Conduction

The transfer of thermal energy through a material by the collision of particles.

15. Radiation

The transfer of thermal energy through electromagnetic waves, without the need for a medium.