Light

Question 1

Define Transverse Wave

Answer 1

oscillation perpendicular to propagation

Question 2

Define Longitudinal Wave

Answer 2

oscillation parallel to propagation

Question 3

What determines colour and brightness of a light wave?

Answer 3

Wavelength = colour
Brightness = amplitude

Question 4

State the Law of Reflection

Answer 4

i=r

angle of reflection is equal to the angle of incidence.

Question 5

Define Refraction

Answer 5

the bending of light due to a change in speed.

Question 6

What are the Rules of Refraction

Answer 6

1) when a light ray enters a medium in which it travels more slowly (larger n), it is refracted towards the normal. (r < i)
2) when a light ray enters a medium in which it travels faster (smaller n), it is refracted away from the normal. (r > i)

Question 7

What is Critical angle and when does it apply?

Answer 7

Applicable when light goes from slower medium into faster medium.
Critical angle, i_c, is the minimum angle for which light is totally internally reflected.

Question 8

What is dispersion?

Answer 8

spreading out of white light into separate colours because slightly different speeds in medium for different wavelengths. In a vacuum, all light travels at the same speed regardless of wavelength.