2.4 The Nature of Waves

Question 1

Progressive wave

Answer 1

A pattern of disturbances travelling through a medium and carrying energy with it, involving the particles of the medium oscillating about their equilibrium positions.

Question 2

Transverse wave

Answer 2

A transverse wave is one where the particle oscillations are at right angles to the direction of travel (or propagation) of the wave.

Question 3

Longitudinal wave

Answer 3

A longitudinal wave is one where the particle oscillations are in line with (parallel to) the direction of travel (or propagation) of the wave.

Question 4

Polarised wave

Answer 4

A polarised wave is a transverse wave in which particle oscillations occur in only one of the directions at right angles to the direction of wave propagation.

Question 5

In phase (waves and wave sources)

Answer 5

Waves arriving at a point are said to be in phase if they have the same frequency and are at the same point in their cycles at the same time.
[Wave sources are in phase if the waves have the same frequency and are at the same point in their cycles at the same time, as they leave the sources.]

Question 6

Unpolarised wave

Answer 6

particle oscillations change randomly in all directions at right angles to the direction of wave travel.