Question

Is the below nuclear reaction fusion or alpha decay?

I'm guessing fusion:

`""^2 H+""^3 H -> ""^1n + ""^4 He`

Answer 1

This is an example of nuclear fusion: two smaller nuclei combining to make a larger one.

Explanation:

As it happens, the larger nucleus formed in this fusion reaction is a helium nucleus, which is the same thing as an alpha particle. But an alpha decay is the thing that would occur if a larger nucleus spontaneously ejected an alpha particle without a collision occurring at the same time. This is a fusion reaction.