Question

Nuclear physics problems.

Please solve question 42 and 43 giving all the steps.

The answer to 42 is C and the answer of 43 is B.

Answer 1

For number 42:

You know from the given equation that two atoms of deuterium yield 3.27 MeV of energy. Your goal is to find out how much energy 2kg of deuterium can produce.

First, you need to figure out how many atoms of deuterium are present in a 2kg sample. To do that, you should find out how massive 1 proton and 1 neutron are (in kilograms) and divide 2kg by that collective mass.
Second, you know two atoms can produce 3.27 MeV, so to find the total energy produced, you divide your total # of atoms by 2 and multiply by 3.27 MeV.
Third, you need to convert this energy unit to Joules by looking up how many Joules are in 1 eV.
Finally, 100W is equivalent to saying 100 Joules per second. So to find the number of seconds (and therefore years) your reaction could light the lamp, simply divide your total energy output (found in the third step) by 100 Joules.

I know that was a long response, but I hope that helps you understand the problem solving process!