The process that mainly takes place in stars to produce energy is:

The operation of a nuclear reactor is said to be critical if the multiplication factor $(K)$ has a value of:

What is the approximate power output of a $_{92}U^{235}$ reactor if it consumes $2 \ kg$ of fuel in $30 \ days$ and each fission releases $185 \ MeV$ of usable energy? (Avogadro's number $N_A = 6.02 \times 10^{26} \text{ atoms/kmol}$)

What is nuclear fission and nuclear fusion?

What will be the energy released in joule, in the process of fission by $1 \text{ mg}$ of ${ }_{92}^{240} U$? Assume energy release per fission is $200 \text{ MeV}$. [Use Avogadro's number as $6 \times 10^{23}$ and $1 \text{ eV} = 1.6 \times 10^{-19} \text{ J}$]

The rest mass of an electron as well as that of a positron is $0.51 \, MeV$. When an electron and a positron annihilate, they produce gamma-rays of wavelength(s):