Why do all electrons emitted during `beta` - decay not have the same energy ?

Explanation

When a neutron is converted into a proton, an electron and neutron are emitted along with it
`._(1)^(1)n rarr ._(1)^(1)H + ._(-1)^(0)e +V`
In `beta` - decay proten remains in the nucleus, but electron and neutrion are emitted with constant energy. The energy of neutrion is not constant. So, all electrons do not have same energy.