Light

Question 1

Explain what happens to a light ray entering the air from water as angle of incidence gradually increases until it is greater than critical angle [4]

Answer 1

refracted ray
refracted ray and reflected ray
angle of refraction increases
refracted ray weaker
total internal reflection

Question 2

State what sort of reflection takes place within and optical fibre and explain why [2]

Answer 2

TIR
angle i > angle c

Question 3

Suggest one reason why the cable is made of thousands of very thin optical fibres [1]

Answer 3

bends easily
less likely to break
more detail

Question 4

Explain why the ray does not change direction as it enters the plastic block [2]

Answer 4

incident ray perpendicular to normal
refracted ray perpendicular to normal

Question 5

Explain what is meant by TIR and the conditions under which it occurs [3]

Answer 5

Angle i>angle c
no light refracted
relected with i=r

Question 6

Angle at which light is shined through a semicircle block is gradually increased from 30 to 90, describe what happens to light [3]

Answer 6

angle of refraction inc
reflected ray brighter
light reflects back into glass

Question 7

State the property of the glass of the prism that causes white light to be split into the different colours of the prism [1]

Answer 7

different speeds for different wavelengths