The control rod in a nuclear reactor is made of

The example of nuclear fusion is

$A$ nuclear fuel rod generates energy at a rate of $5 \times 10^8 \,W/m^3$. It is in the shape of a cylinder of radius $4.0 \,mm$ and length $0.20 \,m$. $A$ coolant of specific heat $4 \times 10^3 \,J \cdot kg^{-1} \cdot K^{-1}$ flows past it at a rate of $0.2 \,kg/s$. The temperature rise in this coolant is approximately ............ $^{\circ}C$.

Energy released when two deuterons $\left({ }_1 H ^2\right)$ fuse to form a helium nucleus $\left({ }_2 He ^4\right)$ is $:$
(Given $:$ Binding energy per nucleon of ${ }_1 H ^2=1.1 \ \text{MeV}$ and binding energy per nucleon of ${ }_2 He ^4=7.0 \ \text{MeV}$) (in $\text{MeV}$)

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

In an $\alpha -$ decay,the kinetic energy of the $\alpha -$ particle is $48 \ MeV$ and the $Q$ value of the reaction is $50 \ MeV$. The mass number of the mother nucleus is (assume that the daughter nucleus is in the ground state).