Pair Production and Annihilation

Question 1

What is an electron volt?

Answer 1

A unit equal to the charge of an electron.

Question 2

What is an electron volt in joules?

Answer 2

1.6x10-19J

Question 3

What is a mega electron volt in joules?

Answer 3

1.6x10-13J

Question 4

What is the equation E=mc2 for?

Answer 4

It is used to find the rest energy of a substance.

Question 5

Could an electron annihilate an anti-muon?

Answer 5

No, only a particle and their corresponding anti-particle can annihilate each other.

Question 6

What is produced when two particles annihilate each other?

Answer 6

Two gamma photons.

Question 7

What is the equation for the energy of gamma photons produced in annihilation?

Answer 7

2mc2 = 2hf
or
mc2 = hf

Question 8

How could you rearrange 2mc2 = 2hf to find the frequency?

Answer 8

mc2/h = f

Question 9

What is pair production?

Answer 9

When a particle and anti particle pair are produced from a gamma photon.

Question 10

What are the condition for pair production?

Answer 10

It must be a high energy gamma photon, and it must be near a nucleus.

Question 11

Why can pair production only occur near a nucleus?

Answer 11

Because it needs the nucleus to take a recoil to conserve momentum.