Use the basic law of radioactive decay to show that radioactive nuclei follow an exponential decay law. Hence obtain a formula for the half-life of a radioactive nuclide in terms of its disintegration constant.

In a nuclear reactor give the function of the

(i) moderator

${{}_{92}\mathrm{P}}^{236}\to {{}_{a}Q}^{141}+{{}_{36}R}^b+3_0{n}^1$ what are the values of $\text{'}a\text{'} \& \text{'}b\text{'}$

In a nuclear reactor give the function of the

(ii) control rods

${{}_{92}\mathrm{P}}^{236}\to {{}_{a}Q}^{141}+{{}_{36}R}^b+3_0{n}^1$ what are the values of $\text{'}a\text{'} \& \text{'}b\text{'}$

In a hypothetical fission reaction ${{}_{92}\mathrm{P}}^{236}\to {{}_{\mathrm{a}}\mathrm{Q}}^{141}+{{}_{36}\mathrm{R}}^{\mathrm{b}}+3_0{\mathrm{n}}^1$ what are the values of $‘a’$ and $‘b’$

In a nuclear reactor give the function of the

(iv) heavy water. In a hypothetical fission reaction

${{}_{92}\mathrm{P}}^{236}\to {{}_{a}Q}^{141}+{{}_{36}R}^b+3_0{n}^1$ what are the values of $\text{'}a\text{'} \& \text{'}b\text{'}$