Unit4: Week 3

Question 1

Why is sin r/sin r used?

Answer 1

When looking at the resultant line- i/r would be a curve and sin i/sin r would be a straight line- which we can use to work out a gradient.

For each value of sin i/sin r the value remains the same- when going from air/a vacuum to a denser medium this gives a constant called the refractive index for the denser medium and is used to show how well a medium refracts light- can be used to identify materials

Question 2

What does critical angle mean fro snells law

Answer 2

r=90

Going from more dense to less dense

Question 3

What are the conversion for micro milli centi kilo mega

Answer 3

Micro- *10^-6
Milli- *10^-3
Centi- *10^-2
Kilo- *10^3
Mega- *10^6

Question 4

What is the photon model of light

Answer 4

Light can be modeled as a wave, this can be seen as it is part of the electromagnetic spectrum which are non mechanical transverse wave. When a wave of light moves past a double slit it results in two waves which consrtuctivly and destructivly interfere. This interference pattern is a wave property. Light can also be modeled as a ray which can show that light traveling in a straight line and it being reflected and refracted.

The photon model of light represent light as discrete (like a particle) packets of energy which have a specific frequency (like a wave). In the photolelectic effect light is shone on a photoelectric material which emmites electrons. The energy of electrons emitted changes when frequency of light changes as opposed to brightness (amplitude), which effects the amount of electrons released. If the wave model was correct then the amplitude would have an effect on the energy. Therefore, the wave and ray models of light can not explain the photoelectric effect and can not be used.