Definitions (All Chapters) Flashcards
Principal axis
Horizontal line passing through the optical centre C of the lens.
Optical centre
Midpoint between the surfaces of the lens on its principal axis.
Focal point
Point at which all rays parallel to the principal axis converge after refraction by the lens.
Focal plane
Plane that passes through the focal point F and is perpendicular to principal axis.
Focal length
Distance between the optical centre and the principal focus of the lens.
Waves / Wave Motion
A periodic motion/ travelling disturbance repeated at regular intervals, which transfers energy from one point to
another without any transfer of matter (or the medium).
Oscillation
A complete to-and-fro motion from one extreme position to the other extreme position, and back.
Crest (or peak)
The highest point of a transverse wave.
Trough
The lowest point of a transverse wave.
Wavefront
An imaginary line joining all points on the waves that are in phase.
Transverse waves
Waves that travel in a direction perpendicular to the direction of vibration of particles.
Longitudinal waves
Waves that travel in a direction parallel to the direction of vibration of particles.
Wavelength
The shortest distance between any 2 points in phase on a wave.
Amplitude
The maximum displacement (of a particle) from the rest position in a wave.
Period
The time taken for one complete oscillation/ wave.
Frequency
Number of complete oscillations per unit time.
Internal energy
Energy store that is made up of total kinetic energy associated with the random motion of the particles and the total potential energy between the particles in the system
Heat capacity
The change of its internal energy per unit change in its temperature.
Specific heat capacity
The change of its internal energy per unit mass for each unit change in its temperature.
Melting
It is the change from the solid state to the liquid state when energy is transferred to the substance without a change in temperature
Latent heat of fusion
The amount of energy transferred to change a substance between the solid and liquid states at constant temperature.
Specific latent heat of fusion
The amount of energy transferred per unit mass of a substance to change between the solid and liquid states at constant temperature.
Boiling
It is the change from the liquid state to the gaseous state when energy is transferred to the substance without a change in temperature.
Latent heat of vaporisation
The amount of energy transferred to change a substance between the liquid and gaseous states, at constant temperature.
