Question

In the fission of U-235, the percentage of mass converted into energy is about

• A. 0.01%
• B. 0.1%
• C. 1%
• D. 10%

Answer 1

The correct option is B 0.1%

When $U^{235}$ is bombarded with a thermal neutron , it breaks into $B{a}^{141}$ and $K{r}^{141}$ along with the liberation of 3 neutrons , this is how the fission of $U^{235}$ takes place.

The fission reaction is : $U^{235}{+}_0{n}^1{⟶}_{56}B{a}^{141}{+}_{36}K{r}^{92}+3_0{n}^1+200MeV$ ,

Energy liberated $E=200Mev$

Now, we have:

$931MeV=1amu$

$200MeV=\frac{200}{931}=0.215amu$, (mass converted into energy)

Mass of $U^{235}=235amu$

Therefore, percentage of mass converted into energy $=\frac{0.215\times 100}{235}=0.09=0.1$%