Explain an example in which heat transfer is necessary.

$A$ $1000 \; MW$ fission reactor consumes half of its fuel in $5.00 \; y$. How much $_{92}^{235} U$ (in $kg$) did it contain initially? Assume that the reactor operates $80 \%$ of the time, that all the energy generated arises from the fission of $_{92}^{235} U$, and that this nuclide is consumed only by the fission process.

Which of the following cannot cause fission in a heavy nucleus?

$A$ nucleus with mass number $A = 240$ and binding energy per nucleon $= 7.6 \,MeV$ breaks into two fragments each of $A = 120$ with binding energy per nucleon $= 8.5 \,MeV$. Calculate the released energy.

The decrease in the mass of Uranium in a nuclear reactor operating at a power of $12 \text{ MW}$ per day is (Energy released in one ${}_{92}U^{235}$ fission is about $200 \text{ MeV}$):

In nuclear fission,the percentage of mass converted into energy is about: (in $\%$)