Waves

Question 1

Amplitude

Answer 1

A wave’s maximum displacement from its equilibrium position

Question 2

Coherence

Answer 2

All the waves have the same wavelength and frequency, as well as having a constant phase difference between them

Question 3

Diffraction

Answer 3

The spreading of waves as they pass through a gap with a similar magnitude to their wavelength

Question 4

Longitudinal wave

Answer 4

A wave that oscillates parallel to the direction of energy transfer

Question 5

Material dispersion

Answer 5

Waves of different wavelengths travel at slightly different speeds through an optic fibre and thus arrive at the end of the fibre at different times, this causes pulses to broaden

This could be fixed by using monochromatic light - one wavelength

Question 6

Modal dispersion

Answer 6

Waves enter an optic fibre at slightly different angles, meaning that the distance each beam has to travel is slightly different, thus arrive at the end at different times, this causes pulses to broaden

This could be fixed by using a single-mode fibre - light only able to follow a very narrow path

Question 7

Polarisation

Answer 7

The restriction of a wave so that it can only oscillate in a single plane, this only occur for transverse wave

Question 8

Total internal reflection

Answer 8

For TIR to occur, the angle of incidence must be greater than its critical angle and the refractive index of the material that the light is travelling into must be less than the refractive index of the material the light is currently in (high to low RI)

Question 9

Transverse wave

Answer 9

A wave that oscillates perpendicular to the direction of energy transfer

Question 10

Frequency

Answer 10

The number of waves that pass a point in a unit time period