OCR GCSE Physics A key terms

A force opposing a vehicle's motion while its brakes slow it down.

A source of electrical energy represented by one long line and one short parallel line; the long line is the positive terminal.

A force directed towards the centre of a circular path. Gravity provides this force for an orbiting planet.

A sequence of fissions in which a neutron released by one fission triggers another.

The change in the energy stored within a material, measured in joules (J).

A physical transition between solid, liquid and gas in which no new substance is formed.

A change in which one or more new substances with different properties are formed.

A store of energy associated with substances and chemical reactions, such as the store in a battery.

A part of an electrical circuit, such as a cell, switch, lamp, resistor or motor.

A standard-symbol drawing that shows the components in a circuit and how they are electrically connected.

A complete conducting path with no breaks, allowing charge to flow around the circuit.

A fixed quantity of gas from which no particles enter or escape.

A system from which matter cannot enter or escape.

The spiral-shaped part of the inner ear in which vibrations stimulate sensory cells, leading to electrical signals in nerve cells.

A short interaction in which objects exert forces on one another and their velocities may change.

The number of particle impacts on a surface during a given time.

An unbroken conducting path around which charge can flow.

One of the perpendicular vectors into which a force can be split.

A unit formed by combining two or more units, usually by multiplication or division, such as metres per second.

A reduction in the volume occupied by a gas as its particles are pushed closer together.

A lens that is thinner in the middle than at its edges and makes parallel rays diverge.

A material through which electric charge can flow; a metal wire is a common example.

The principle that the total electric charge is the same before and after a nuclear decay.

The rule that energy cannot be created or destroyed; in a closed system, its total amount remains constant.

The principle that mass is neither created nor destroyed during a physical change; the total mass of a closed system remains constant.

The principle that the total momentum of a system remains constant when no resultant external force acts on it.

The temperature condition in which the average kinetic energy, and therefore the typical speed, of the gas particles does not change.