Corrections

Question 1

As you increase the distance between grating what happens to the angle

Answer 1

The angle will be smaller

Question 2

How can conduction take place in a semi conductor at room temperature

Answer 2

Valence and conduction band has a small gap

Electrons have sufficient energy to move from valence to conduction band

Question 3

A potential difference is produced when photons enter the layer between the p-type and n-type materials, what is this effect?

Answer 3

Photovoltaic effect

Question 4

Light is red shifted from galaxies, explain this in reference to the Big Bang theory ?

Answer 4

Red shift is evidence that galaxies are moving away from each other which is

Question 5

A group of particles known as fermions consists of ?

Answer 5

Quarks and leptons

Question 6

What is meant by the critical angle?

Answer 6

Angle of incidence when angle of refraction is at 90°

Question 7

Explain why a spectrum occurs when white light is shone into a prism

Answer 7

Different colours have different refractive indices

Question 8

Explain the steps, using band theory, of the photovoltaic effect?

Answer 8

Electrons absorb energy from photons

Electrons move from valence band to conduction band

Electrons move towards n-type semi-conductor