Question

Write the approximate value of the energy released in the fission of one nucleus of ${}_{92}^{235}\text{U}$. What is the reason for it?

Answer 1

Due to fission of one uranium nucleus, nearly 190 MeV of energy is released.
The reason for emission of this energy is the loss in mass, i.e. the sum of masses of product nuclei is less than the sum of mass of the parent nucleus and the neutron.