Physics

Absolute zero

Lowest possible temperature

Acceleration

Change of velocity per unit time

Acceleration of free fall

9.8 m/s-2

Accretion model

Build up of mass due to gravitational attraction between smaller particles leading to the formation of the solar system

Advantages of high violate transmission if electricity

Lower power loss in transmission cables

Air resistance

Frictional force opposing the motion of a body of moving air

Alpha particles

Radiation consisting of helium ions with a doubled positive charge

Alternating current

The direction of current flow reverses repeatedly

Ammeter

Measures electric current

Amplitude

Heigh of crest of a wave

Analogue

Continuously varying

Angle of incidence

The angle between the incident ray and the normal to a surface

Angle of reflection

Angle between reflected ray and the normal to a surface

Angle of refraction

Angle between reflected refracted ray and normal to the surface

Anode

Positively charged electrode

Area of a circle

πr²

Area of a square or rectangle

Length x breadth

Area of a triangle

½ base x height

Armature

Coil and core of an electric motor

Average orbital speed

V = 2πr / T

Average speed

Distance moved / time taken

Background radiation

Ever-present radiation resulting from cosmic rays from outer space and radioactive materials in the rocks, air and buildings