how does e=mc^2 relate to fussion?

Question

random wuestion.. i wanted to see if you guys could explain this a little better than my teacher :)

Answer 1

There are two ways of achieving nuclear power, one by splitting atoms (fission), the other by combining them (fusion). For the D-T fusion, for example, an isotope of an hydrogen atom can be combined with another isotope of an hydrogen atom to make a helium atom, giving off an excess neutron. But if the helium atom and that excess neutron are weighed together, they weigh less than the original two isotopes of hydrogen that fused together. The missing mass has been converted into energy. To figure how much energy was generated by this missing mass, the equation E = mc^2 is used.

Why some mass should vanish is because the total nuclear binding energy required in Deuterium and Tritium nuclei (D-T fusion) is slightly greater than the nuclear binding energy in a helium nucleus. When bound, this difference in energy is manifested as mass.

Answer 2

It relates to fusion and fission on the following way: Each proton and neutron has a standard mass. So when you add the masses of each proton and neutron in an atom together, you get it's molecular mass, right? WRONG! It's actually smaller than you would expect. This is called the nuclear defect. This mass difference relates to the nuclear binding energy in the equation e = mc^2, where c is the speed of light, or 3 x 10^8 m/s. For each 1 atomic mass unit (amu) difference, there will be the energy of 931.5 MeV (mega electric volts).

Answer 3

I thought "rhsaunder..." above answered it pretty well....I will just like to add that the quantity 'm' in Einstein's Energy-mass equation refers to an actual loss in mass in a nuclear fission or a nuclear fusion. In both these nuclear reactions, there is a loss of mass, usually in amu, now called just 'u' unified atomic mass.
This mass has to be converted to kilograms, and then you multiply with the square of the speed of light, to obtain the actual nuclear energy (in J) that is released.

It really depends on how detail you want the answer to be.

Nuclear fusion, right now, is difficult to control on earth due to the very high temperature required for it to take place.There are ongoing researches though. However, it is happening in the Sun (the smallest star in our galaxy) and all the stars in the universe as you read this answer. The temperatures in the sun and the stars are of the order of millions and millions of deg C.

So the sun and the stars are slowing losing mass. But don't worry. The sun will continue to burn and lose mass for a few billions years to come, before it completely becomes dark

Answer 4

Suppose that you have four atoms of hydrogen, each weighing 1.008 amu. You contrive to fuse these to make helium, weight 4.003 amu. There is 0.029 amu of mass not accounted for; where does it go? Energy, according to e = mc^2. It will show up as kinetic energy of the two beta particles (electrons) which are released by the reaction(s), and also as some energy in neutrinos.

Answer 5

in fusion as well in fission there is loss of mass.where this mass goes? this mass gets converted in to energy and the amount of the energy formed can be given by the equation E=mc^2 where m is the change(loss) in the mass.c is the velocity of light and E the equivalent energy formed.