# Homework Help: Nuclear physics problem

1. May 7, 2012

### Abidal Sala

1. The problem statement, all variables and given/known data
Calculate the energy released from the following reaction:-
2(H) ---> He [mass number for H = 2, atomic number for H = 1, mass number for He = 4, atomic number for He = 2]
Data: the mass of the H in the reaction = 2.0242 u, and its kinetic energy = 925 M.ev
and the mass of He = 4.0015 u

2. Relevant equations
E = mC^2
minimum energy required to split nucleons = Δm * 931
mass of nucleus = (Number of protons * mass of protons) + (number of neutrons * mass of neutrons)

3. The attempt at a solution
i really have no idea how this is done but the only thing i can think of is E = (difference between the masses) * C^2
so 1.9773 * 3 * 10^8 = 593190000 ??

2. May 7, 2012

### matt_crouch

you need to balance the reaction equation out so that you have basically

2(mhydrogen)= 1(mass of helium) + Δm

then you can calculate the difference in mass.
I can see one mistake and that is that you have used the value for C instead of C^2.
Also note that the hydrogen has an initial kinetic energy I believe so don't forget to add that

3. May 7, 2012

### tms

The nuclear mass also includes the binding energy, that is, the energy that is released when the nucleus splits.