In the decay sequence: U 92 238 → - x 1 Th 90 234 → - x 2 Pa 91 234 → - x 3 Z 234 → - x 4 Th 90 234 x 1 , x 2 , x 3 and x 4 are the particles/ radiation emitted by the respective isotopes. The correct option(s) is/are:

x 1 will deflect towards the negatively charged plate.

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The half life of a radioactive isotope is three hours. If the initial mass of the isotope were 256 g, the mass of it remaining undecayed after 18 hours would be

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Important Questions on Nuclear Chemistry

MEDIUM

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

Draw the curve showing the variation of binding energy per nucleon as a function of mass number

A

. Explain the stability of nucleus from the curve

HARD

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

Define the term ‘decay constant’ of a radioactive sample. The rate of disintegration of a given radioactive nucleus is

10000

disintegrations and

5, 000

disintegrations after

20 h o u r

. and

30 h o u r

. respectively from start. Calculate the half-life and the initial number of nuclei at

t = 0

EASY

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

What is meant by half life of a radioactive substance? Write its relation with decay constant.

EASY

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

In the radioactive disintegration series

_{90}^{232} T h \to_{82}^{208} P b,

involving

α

and

β

decay, the total number of

α

and

β

particles emitted are

EASY

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

Consider, the radioactive disintegration

{}_{82}A^{210} \to B \to C \to {}_{82}D^{206}

The sequence of emission can be

MEDIUM

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

^{227} A c

has a half-life of 22 years with respect to radioactive decay. The decay follows two parallel paths:

^{227} Ac \to^{227} T h

and

^{227} Ac \to^{223} F r

. If the percentage of the two daughter nuclides are

2.0

and

98.0

, respectively the decay constant (in

y e a r^{- 1}

) for

^{227} Ac \to^{227} T h

path is closest to

MEDIUM

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

Predict the element resulting from two

α

decay, two consecutive

β

decay and one

γ

decay of

Th - 232

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Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

In the radioactive decay process

Question Image

1. A and B are isobars

2. A and D are isotopes

3. C and D are isobars

4. A and C are isotopes

EASY

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

The decay constant which is the reciprocal of the time duration for which the number of the atoms of radioactive substance falls to

EASY

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

If the quantity of a radioactive element is doubled, the rate of disintegration will

MEDIUM

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

In the decay sequence:

${}_{92}^{238}U \overset{- x_{1}}{\to} {}_{90}^{234}{Th} \overset{- x_{2}}{\to} {}_{91}^{234}{Pa} \overset{- x_{3}}{\to} {}^{234}Z \overset{- x_{4}}{\to} {}_{90}^{234}{Th}$

$x_{1}, x_{2}, x_{3}$ and $x_{4}$ are the particles/ radiation emitted by the respective isotopes. The correct option(s) is/are:

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Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

A bacterial infection in an internal wound grows as

N^{'} (t) = N_{0} e x p (t)

, where the time

t

is in hours. A dose of antibiotic, taken orally, needs 1 hour to reach the wound. Once it reaches there, the bacterial population goes down as

\frac{d N}{d t} = - 5 N^{2}

. What will be the plot of

\frac{N_{0}}{N}

t

after

1

hour?

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Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

A nucleus

X

captures a

β

particle and then emits a neutron and

γ

ray to form

Y . X

and

Y

are:-

HARD

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

A and B are two substances undergoing radioactive decay in a container. The half life of A is

15 \min

and that of B is

5 \min

. If the initial concentration of B is

4

times that of A and they both start decaying at the same time, how much time will it take for the concentration of both of them to be same? ________min.

MEDIUM

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

The ratio of the binding energies of three nuclei is

1 : 4 : 9

. If the ratio of their nuclear radii is

1 : 2 : 3

, the nuclei in the decreasing order of the stability can be arranged as

MEDIUM

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

{}_{93}^{239}{Np}

is a

β

-emitter, but the product is also radioactive and give

{}^{235}U

. Which particle(s) is/are emitted by the product?

EASY

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

Select the correct option

HARD

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

A radioactive sample is emitting

64

times radiations than non-hazardous limit. If its half life is

2 h

, after what time it become non hazardous?

HARD

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

{}_{92}^{238}U

is known to undergo radioactive decay to form

{}_{82}^{206}{Pb}

by emitting alpha and beta particles. A rock initially contained

68 \times 10^{- 6} g

{}_{92}^{238}U

. If the number of alpha particles that it would emit during its radioactive decay of

{}_{92}^{238}U

{}_{82}^{206}{Pb}

in three half-lives is

Z \times 10^{18}

, then what is the value of

Z

HARD

Chemistry>Physical Chemistry>Nuclear Chemistry>Applications of Radioactivity

In the nuclear transmutation

_{4}^{9} Be + X ⟶_{4}^{8} Be + Y

, identify

(X, Y)

The half life of a radioactive isotope is three hours. If the initial mass of the isotope were 256 g, the mass of it remaining undecayed after 18 hours would be

Important Questions on Nuclear Chemistry

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