# Homework Help: Calculating energy released by fission.

1. May 3, 2015

### nima rahmani

hey guys.
i have answered my question but i am not quite sure about it.
Four hydrogen atoms fuse to produce one helium nucleus.calculate how many MeV of energy is released in this
process. You are calculating how much energy is released by the fusion of four hydrogen atoms.

what i have done: average binding energy 4 H: 0.4*4 MeV = 1.6MeV
Then: Average binding energy of He: 9 MeV.
SO the energy release would be 9 MeV - 1,6MeV = 7.4 MeV.

THANKS.

2. May 3, 2015

### rude man

In this (fictional) fusion process, no isotopes are involved, no positron, gamma or other subparticles are involved, so I would just argue conservation of mass-energy. I don't know how far along you are in particle physics, course-wise.

3. May 3, 2015

### Staff: Mentor

Where does the 9 MeV value for helium come from and what does it mean?

This does not work - two protons have to convert to neutrons, and this reaction also produces something else.
Instead of using binding energies, is easier to look up the masses of all relevant particles, and to compare them.