The total energy released if 47 g of $$^{235}\text U$$​ undergoes fission (disintegration energy per event, Q = 200 MeV, Avogadro's number = 6.02 × $$10^{23}$$​ nuclei/mol) is close to:

Correct option is B

Given 

​$$\text{Disintegration energy per event } (Q) = 200 \ \text{MeV} \\\text{Avogadro's number } (N_A) = 6.02 \times 10^{23} \ \text{nuclei/mol} \\\text{Mass of } {}^{235}U = 47 \ \text{g} \\\text{Molar mass of } {}^{235}U (M_0) = 235 \ \text{g/mol}$$

$$\text{1. Number of nuclei in 47 g of } {}^{235}U: \text{ The number of nuclei in the given mass of } {}^{235}U \text{ is given by:} \\N = \frac{N_A}{M_0} \times m$$

$$N = \frac{6.02 \times 10^{23}}{235} \times 47 \\N = 1.204 \times 10^{23} \ \text{nuclei}$$

$$\text{2. Total energy released: The total energy released is given by:} \\E = N \times Q$$

$$\text{Convert the disintegration energy per event } (Q) \text{ from MeV to joules:} \\1 \ \text{MeV} = 1.6 \times 10^{-13} \ \text{J}$$

$$\text{So,} \ Q = 200 \ \text{MeV} = 200 \times 1.6 \times 10^{-13} = 3.2 \times 10^{-11} \ \text{J.}$$

$$\text{Now, calculate the total energy released:} \\E = 1.204 \times 10^{23} \times 200 \times 1.6 \times 10^{-19} \\E = 3.85 \times 10^{12} \ \text{J}$$​​​​​​​​