Chapter 13 - Light Waves

Question 1

What is refraction? (1)

Answer 1

• change in direction of waves at a boundary

Question 2

State the equation linking refractive index, angle of incidence and angle of refraction (1)

Answer 2

refractive index = sin i / sin r

Question 3

Answer 3

• Draw around block
• Mark positions of incident and emergent rays
• remove block and draw refracted ray
• measure i and r
• measure angles to the normal
• range of values

Question 4

State two conditions required for total internal reflection to happen [2 marks]

Answer 4

• Must be more (optically) dense to less (optically) dense change
• Angle of incidence > critical angle;

Question 5

Suggest one advantage of sending signals using optical fibres [1 marks]

Answer 5

• Less prone to noise

Question 6

Answer 6

D

Question 7

State two ways in which light waves change as they pass into the glass (2)

Answer 7

• waves slow down
• waves change direction/bend/angle;
• wavelength decreases;