A level Physics definitions

Radian

Radian

A unit of angle

Gravitational Potential

The amount of work done in moving a unit mass from an infinite distance to that point.

Specific Heat Capacity

The amount of energy required to increase the temperature of 1kg of a substance by 1 degree.

Specific Latent Heat

The amount of energy required to change the state of 1kg of a substance without a change of temperature.

Ideal gas

A hypothetical gas that has molecules with no interactions and occupies negligible space so it obeys the ideal gas law.

First law of thermodynamics

The increase in internal energy of a system is equal to the sum of the energy transferred to it through heating and work done on the system.

Angular Frequency

A measure of an object’s angular displacement per unit time.

Electric field

A region surrounding a charged object which causes a non-contact force to be exerted on any charged object placed within the field.

Magnetic Field

A region surrounding a magnet or current-carrying wire that will exert a force on any other magnetic material

Electric potential

The work done per unit charge on a positive test charge in bringing it from infinity to a chosen point in the field.

Coulomb’s Law

The size of the force that acts between two point charges is proportional to the product of their charges and inversely proportional to the square of their separation.

Capacitance

The charge stored per unit pd

Magnetic Flux Density

The force per unit current per unit length on a current-carrying wire placed at 90º to the field lines.

Binding Energy

The energy required to split a nucleus into its individual nucleons.

Mass Defect

The difference in mass between a nucleus and the sum of the masses of its constituent nucleons.

Activity

The rate of decay of the radioactive nuclei in a given isotope.

Decay Constant

The probability of a decay occurring per unit time.

Half-Life

The time taken for half of the radioactive nuclei to decay.

Acoustic Impedance

The product of the speed of sound through a given medium, and the density of the medium.

Hubble’s Law

The speed of a galaxy moving away from ours is proportional to its distance away from us.

Wien’s Displacement Law

The peak wavelength of emitted radiation is inversely proportional to its absolute temperature.

Simple Harmonic Motion

Motion where the acceleration of an object is directly proportional, and in the opposite direction, to its displacement.