how do i calculate the power of nuclear fission like uranuim 235 bombarded by neutron?

Answer 1

I think it's sort of hard to tell because each reaction is random and makes different end materials. For example, U235 could turn into let's say Rb90 and Cs144 or Kr and Ba, or other stuff, and in each reaction both the amount of neutrons released and the amount of energy released is different. I think they do estimates statistically...lol this is hard stuff to figure out. But if you assume let's say that most reactions turn up Rb and Cs, which is a wrong assumption, then you have to subtract the mC^2 of the end materials from mc^2 of U and you get one reactions energy release, then you have to know how fast this takes place, divide by time and multiply in number of atoms! Easy! ...God, I wonder how they can tell how powerfull a bomb is? Is it just an estimate?
I forgot to say that an estimate of how many released nuetrons are likely to hit how many atoms is important too. There is a reason why atomic physics has a bad reputation!

Answer 2

Calculate the mass of the products and subtract them from the mass of U235+neutron mass, convert into energy using E=mc^2. The kinetic energies can usually be ignored but you could also include the before and after kinetic energy if you know them.
By power I assume you mean energy, but power is energy per unit time so you would need the time of fission to get power.

Answer 3

I won't tell you that bad man, what are you up to?