WAVES DEFINITIONS

Question 1

Amplitude

Answer 1

The maximum displacement of a particle from its equilibrium position.

Question 2

Antinode

Answer 2

A position of maximum displacement in a stationary wave

Question 3

Cladding

Answer 3

A protective layer on an optical fibre that improves the tensile strength, prevents scratching and signal transfer between adjacent fibres

Question 4

Coherence

Answer 4

Waves are coherent if they emit waves with a constant phase difference, and they have the same wavelength and frequency

Question 5

Diffraction grating

Answer 5

A plate with many closely ruled parallel slits

Question 6

Diffraction

Answer 6

The spreading of waves as they pass through a gap or near an edge that is similar to their wavelength

Question 7

Electromagnetic Wave

Answer 7

A wavepacket of photon consisting of transverse electric and magnetic waves in phase and at right angles to eachother

Question 8

Frequency

Answer 8

The number of complete wave cycles that pass a point per second

Question 9

Interference

Answer 9

The formation of points of cancellation or reinforcement where two coherent waves pass through eachother

Question 10

Laser

Answer 10

A light source that produces a parallel and coherent beam of monochromatic light

Question 11

Longitudinal Wave

Answer 11

A wave with oscillations that are parallel to the direction of wave propagation

Question 12

Material Dispersion

Answer 12

Waves of different wavelengths travel at different speeds through an optical fibre

And so reach the end of the fibre at different times

Causing pulse broadening

Question 13

Modal Dispersion

Answer 13

Waves enter an optical fibre at slightly different angles, meaning the distance each beam has to travel is different

The beams reach the end at different times

Causing pulse broadening

Question 14

Node

Answer 14

A fixed point of minimum displacement in a stationary wave

Question 15

Optical Fibre

Answer 15

A thin transparent glass fibre through which signals are passed

Question 16

Path difference

Answer 16

the difference in distances from two coherent sources to an interference fringe

Question 17

Phase Difference

Answer 17

The difference in phase between two points on a wave

Question 18

Polarisation

Answer 18

The restriction of a wave so that it can only oscillate in a single plane

Question 19

Pulse Broadening

Answer 19

The elongation of a signal passed down an optical fibre

Question 20

Stationary Wave

Answer 20

A wave that stores energy

Question 21

Transverse Wave

Answer 21

A wave with oscillations that are perpendicular to the direction of wave propagation

Question 22

Total Internal Reflection

Answer 22

A light ray travelling in a substance is totally internally reflected at a boundary with a substance of a lower refractive index, if the angle of incidence is greater than the critical angle

Question 23

Wavelength

Answer 23

The distance between two identical positions on two adjacent waves

Question 24

Young’s Double Slit Experiment

Answer 24

Demonstrated the diffraction of light by passing monochromatic light across two narrow slits and observing the resulting pattern of bright and dark fringes.

Question 25

Principle of Superposition

Answer 25

When two waves cross, the resultant displacement equals the vector sum of the individual displacements.