Nuclear Physics

Question 1

Use band theory to explain how an increase in temperature affects the resistance of a metal.

Answer 1

In a metal, the conduction band overlaps the valence band. So any increase in temperature does not cause an increasing the number of free electrons. the increased temperature causes an increase in vibration for the electrons that increases the resistance. This is because the lattice vibrations restrict the movement of electrons.

Question 2

What is the radioactive decay constant?

Answer 2

It is the probability of the decay (of a nucleus) per unit time.

Question 3

By reference to the intensity of light, state one piece of evidence provided by the photoelectric effect for a particulate nature of light.

Answer 3

(maximum) the energy of emitted electrons is independent of intensity.
or
no emission of electron below the threshold frequency if the intensity
or
no emission of electrons when photon energy is less than work function (energy) regardless of intensity,