What is the maximum frequency photon of one of the photons produced when a electron and positron annihilate each other?

First we must remember that a positron is the antiparticle of the electron, meaning that they will both have the same amount of rest energy (0.510999 MeV) however since annihilation produces 2 gamma photons each photon will have the same rest energy as one of the particles (0.510999 MeV). We then use the equation E=hc/λ rearranged to λ=hc/E and then sub in:(6.63x10-34)(3x108)/(0.511x106)(1.60x10-19) Notice here that in the denominator i have converted (0.510999 MeV) into MeV and then multiplied by the charge of an electron to get the energy in Joules (J) .
This then gives us the maximum wavelength of a single photon during a photon-positron annihilation: 2.43x10-12m

Related Physics A Level answers

All answers ▸

A small ball of mass 150 g is placed at a height of 20cm above the ground on an incline of 35°. It is released and allowed to roll down the slope; what will be the ball's speed when it reaches the ground? Assume friction and air resistance can be ignored.


A man weighing 600N steps on a scale that contains a spring. The spring is compressed 1cm under their weight. Find the force constant of the spring and total work done on its compression.


A spacecraft needs to be slowed down from a speed of 96m/s to 8.2m/s. This can be done by firing an object as the spacecraft is moving. If the mass of the spacecraft is 6730kg and the object is 50kg, calculate the velocity of the ejected object.


Describe the interaction that is responsible for keeping protons and neutrons together in a stable nucleus.