Answer 1

Given:
Rate of development of thermal energy = 300 MW
Average energy released per fission = 200 MeV
Let N be the number of atoms disintegrating per second.
Then, the total energy emitted per second will be

`N xx 200 xx 10^6 xx 1.6 xx 10^-19` = Power

`N xx 200 xx 10^6 xx 1.6 xx 10^-19 = 300 xx 10^6` atoms

⇒ `N = 3/(2 xx 1.6) xx 10^19 = 3/3.2 xx 10^19` atoms

6.023 × 10²³ atoms = 238 gm of U²³⁵

`3/3.2 xx 10^19` atoms will present in `(238 xx 3 xx 10^19)/(6 xx 10^23 xx 3.2) = 3.7` mg