Explanation:
According to the law of the conservation of mass, 'mass is conserved in a chemical reaction. The mass cannot be created nor be destroyed in a chemical process'.
This law holds true for the burning of wood also. Although the wood burns to produce ash which weighs less than wood but also, it produces some soot and other gases and the sum of the masses of all these is equal to the sum of the masses of wood and oxygen that reacted with it.
13 because an atom has the same number of protons as neutrons
So for D you have to find energy right
from c you get wavelength Lambda
so on D use this
E = Hc / lambda
c is given 1.5 x 10 ^20
h = 6.624 x 10^-34
and then you get answer for energy
