AQA GCSE Combined Science Physics - Energy

What is kinetic energy?

The energy an object has due to its motion.

What factors affect the kinetic energy of an object?

Its mass and speed — heavier and faster objects store more kinetic energy.

What is gravitational potential energy?

Energy stored in an object because of its height above the ground.

What factors affect gravitational potential energy?

Mass, height, and gravitational field strength (usually 10 N/kg on Earth).

What is elastic potential energy?

Energy stored when an object is stretched or compressed.

What is work done?

Energy transferred when a force moves an object over a distance.

What is the relationship between energy transferred and work done?

They are the same — both measured in joules (J).

What is power in physics?

The rate at which energy is transferred or work is done.

What are the units of power?

Watts (W)

What does it mean if a device is more powerful?

It transfers more energy in less time.

What is efficiency?

A measure of how much input energy is usefully transferred.

How can we improve efficiency?

Reduce wasted energy, e.g. by lubricating, insulating, or streamlining.

What is dissipation of energy?

When energy spreads out into the surroundings and becomes less useful (e.g., heat or sound).

What is specific heat capacity?

How much energy is needed to raise 1 kg of a material by 1°C.

Why do metals have low specific heat capacities?

They heat up quickly, needing less energy per degree of temperature increase.

What is thermal conductivity?

A measure of how well a material conducts heat — higher values = quicker transfer.

How does conduction transfer heat?

Particles vibrate and transfer energy to neighbouring particles — works best in solids.

How does convection work in fluids?

Warm, less dense fluid rises and cooler fluid sinks, creating a convection current.

What is infrared radiation?

Heat transferred by waves — doesn’t need particles (works in space).

How do black and shiny surfaces affect radiation?

Black, matte surfaces absorb and emit better; shiny surfaces reflect heat.

Why is insulation used in homes?

To reduce heat loss and improve energy efficiency.

What are non-renewable energy sources?

Fossil fuels (e.g. coal and gas) and nuclear

What are renewable energy sources?

Wind, solar, hydroelectric, tidal, biomass, geothermal — won't run out.

What are some disadvantages of renewable energy?

Some are weather-dependent, take up space, or can harm wildlife.

What is base load supply?

The minimum constant electricity supply needed — usually provided by reliable sources like nuclear.