Photon Energy and Pair Annihilation

The video tutorial explains the concept of pair annihilation, where an electron and a positron collide and annihilate each other, producing gamma ray photons. It sets up a problem where an electron and a positron, traveling at the same speed but in opposite directions, collide to produce two identical gamma ray photons. The tutorial walks through the calculation of energy conservation before and after the collision, ultimately determining the energy of each photon produced.

What happens when an electron collides with a positron?

• They create a black hole.

• They bounce off each other.

• They annihilate each other, producing gamma ray photons.

• They merge to form a neutron.

What is conserved during pair annihilation?

• Only kinetic energy

• Momentum

• Only mass

• Mass-energy

Why do positrons not survive long in nature?

• They are absorbed by protons.

• They decay into other particles.

• They quickly annihilate with electrons.

• They are unstable particles.

In the problem setup, what is the speed of the electron and positron?

• 5,000 m/s

• 1,000 m/s

• 3,000 m/s

• 10,000 m/s

What is produced when the electron and positron collide in the problem setup?

• One gamma ray photon

• Two identical gamma ray photons

• A neutron and a neutrino

• A proton and an antiproton

Why is the kinetic energy term considered negligible in the photon energy calculation?

• Because the particles are at rest.

• Because the particles are moving faster than light.

• Because the speed of light is much greater than the speed of the particles.

• Because the kinetic energy is zero.

What is the rest mass energy of an electron in Mega electron volts (MeV)?

• 2.044 MeV

• 1.022 MeV

• 0.511 MeV

• 0.255 MeV

How many identical photons are produced in the pair annihilation problem?

• Three

• Two

• Four

• One

What is the energy of each photon produced in the problem setup?

• 0.255 MeV

• 1.022 MeV

• 0.511 MeV

• 2.044 MeV

What is the significance of the speed of light in the photon energy calculation?

• It is used to calculate the kinetic energy.

• It is used to convert mass to energy.

• It is used to determine the speed of the photons.

• It is used to calculate the momentum of the particles.