The S.I. unit of radioactivity is
(a) Roentgen          (b) Rutherford
(c) Curie                (d) Becqueral

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High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A radioactive material has an initial amount 16 gm. After 120 days it reduces to 1 gm, then the half-life of radioactive material is
(a) 60 days              (b) 30 days
(c) 40 days              (d) 240 days

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High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The equation ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}\to {}_{\mathrm{Z}+1}{}^{\mathrm{A}}\mathrm{Y}+{}_{-1}{}^{0}\mathrm{e}+\overline{\mathrm{v}}$   represents-
1. $\mathrm{\beta }$-emission

2. $\mathrm{\alpha }$-emission

3. ${\mathrm{e}}^{-}$ capture

4. Fission

Concept Questions :-

Types of decay
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The activity of a sample of a radioactive material is ${\mathrm{A}}_{1}$, at time ${\mathrm{t}}_{1}$ and ${\mathrm{A}}_{2}$ at time ${\mathrm{t}}_{2}$ (${\mathrm{t}}_{2}$>${\mathrm{t}}_{1}$). If its mean life T, then
(a) ${\mathrm{A}}_{1}{\mathrm{t}}_{1}={\mathrm{A}}_{2}{\mathrm{t}}_{2}$            (b) ${\mathrm{A}}_{1}-{\mathrm{A}}_{2}={\mathrm{t}}_{2}-{\mathrm{t}}_{1}$
(c) ${\mathrm{A}}_{2}={\mathrm{A}}_{1}{\mathrm{e}}^{\left({\mathrm{t}}_{1}-{\mathrm{t}}_{2}\right)/\mathrm{T}}$    (d) ${\mathrm{A}}_{2}={\mathrm{A}}_{1}{\mathrm{e}}^{\left({\mathrm{t}}_{1}/{\mathrm{t}}_{2}\right)\mathrm{T}}$

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Difficulty Level:

Nucleus produced due to $\mathrm{\alpha }$-decay of the nucleus ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}$ is

(a) ${}_{\mathrm{Z}+2}{}^{\mathrm{A}+4}\mathrm{Y}$                     (b) ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{Y}$
(c) ${}_{\mathrm{Z}-2}{}^{\mathrm{A}-4}\mathrm{Y}$                     (d) ${}_{\mathrm{Z}-4}{}^{\mathrm{A}-2}\mathrm{Y}$

Concept Questions :-

Types of decay
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Which of the following processes represents a gamma-decay

(a) ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}+\mathrm{\gamma }\to {}_{\mathrm{Z}-1}{}^{\mathrm{A}}\mathrm{X}+\mathrm{a}+\mathrm{b}$
(b) ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}+{}_{0}{}^{1}\mathrm{n}\to {}_{\mathrm{Z}-2}{}^{\mathrm{A}-3}\mathrm{X}+\mathrm{c}$
(c) ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}\to {}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}+\mathrm{f}$
(d)

Concept Questions :-

Types of decay
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The half-life of ${}_{215}\mathrm{At}$ is 100 $\mathrm{\mu s}$. The time taken for the radioactivity of a sample of ${}_{215}\mathrm{At}$ to decay to 1/16th of its initial value is
(a) 400 $\mathrm{\mu s}$               (b) 6.3 $\mathrm{\mu s}$
(c) 40 $\mathrm{\mu s}$                 (d) 300 $\mathrm{\mu s}$

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Difficulty Level:

The half-life of a radioactive substance is 48 hours. How much time will it take to disintegrate to its $\frac{1}{16}$th part

(a) 12 h             (b) 16 h
(c) 48 h             (d) 192 h

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Difficulty Level:

A radioactive substance has an average life of 5 hours. In a time of 5 hours
(a) Half of the active nuclei decay
(b) Less than half of the active nuclei decay
(c) More than half of the active nuclei decay
(d) All active nuclei decay

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High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Which of the following radiations has the least wavelength

(a) X-rays              (b) $\mathrm{\gamma }$-rays
(c) $\mathrm{\beta }$-rays              (d) $\mathrm{\alpha }$-rays

Concept Questions :-

Types of decay