Module 4 - Waves (Diffraction and Polarisation)

Question 1

What is meant by polarisation

Answer 1

restricting a transverse wave to oscillate in a single plane

Question 2

What is meant by unpolarised light

Answer 2

When light radiates in all planes

Question 3

Why cant longitudinal waves be polarised

Answer 3

All oscillations are already parallel to the direction of energy transfer meaning it is already in one plane and therefore effectively already polarised

Question 4

What is meant by partial polarisation

Answer 4

• When a wave has more oscillations in one plane than another

Question 5

What is meant by diffraction

Answer 5

The spreading out of a wavefront as it passed through a gap or passed and objecT

Question 6

What characteristics remain the same during diffraction

Answer 6

• The wave speed, because the medium doesnt change
• frequency, because it is determined from the source

Question 7

When are the effects of diffraction the most significant

Answer 7

When the width of the gap is comparable to the wavlength of a wave

Question 8

What field is ignored when looking at polarisation

Answer 8

The magnetic field

Question 9

When does circular polarisation occur

Answer 9

When 2 seperate light rays approach the viewer with a phase difference of an odd integer multiple of 180