Radioactivity all Around

Geiger counter is used for detecting radioactive radiation.

Which of these instruments are used to detect or monitor nuclear radiation ?

Discuss background radiation.

Define radiation.

In a radioactive decay chain, the initial nucleus is ${ }_{90}^{232}\mathrm{Th}$. At the end, there are $6$ $\alpha$-particles and $4\beta$-particles which are emitted. If the end nucleus is ${}_{\mathrm{Z}}^{\mathrm{A}}\mathrm{X}, A$ and $Z$ are given by:

Man-made radioactivity is also known as

Artificial radioactivity was discovered in which year?

Radioactivity was first discovered in which year?

Choose the SI unit of radioactivity.

Who discovered natural radioactivity?

The half life of a radioactive material is $5$ years. The probability of disintegration for a nucleus in $10$ years is :-

A nucleus $X$ whose mass number is $36 ,$is initially at rest. It is dis-integrated into $\alpha$ particle and a doughter nucleus $Y.$ If no $\gamma$ emmission is there, then chose the incorrect atternative.

Different nuclides spontaneously undergo radioactive decay, emitting either $\alpha ,\beta$ or $\gamma$ radiation. Which of the following correctly identifies all the emissions that do not have discrete energies?

The energies of alpha particles and of gamma rays emitted in radioactive decay are discrete. This observation is evidence for

Which of the following causes the greatest number of ionizations as it passes through $1\mathrm{cm}$ of air? (The total energy of the ionizing radiation is the same.

A nucleus with $\mathrm{Z}=92$92$ emits the following in a sequence $:\alpha ,\alpha ,{\beta }^{-},{\beta }^{-},\alpha ,\alpha ,\alpha ,\alpha ,{\beta }^{-}{\beta }^{-},\alpha ,{\beta }^{+},$ ${\beta }^{+},\alpha .$ The $Z$ of the resulting nucleus is-

Write law of Radioactive decay. Using the exponential decay law derive expressions for half life and mean life of a radioactive element.

At a given instant there are $25\%$ of undecayed radioactive nuclei in a sample. After $20 \mathrm{s},$ the number of undecayed nuclei reduces to $12.5\%.$ What is the time in which the number of undecayed nuclei will further reduce to $3.125\%$ of the sample ?

A radioactive sample has an initial concentration $N_0$ of nuclei. Then,

Nuclei of a radioactive element A are being produced at a constant rate α. The element has a decay constant λ. At time t = 0, there are N₀ nuclei of the element. If α = 2N₀ λ , calculate the number of nuclei of A after one half-life of A.