Consider two nuclei of the same radioactive nuclide. One of the nuclei was created in a supernova explosion ${\rm{5}}\,\,\,{\rm{billion}}\,\,{\rm{years}}$ ago. The probability of decay during the next time is

Nuclei created in explosion decays first

Nuclei created in the reactor decays first

In $_{88}R{a^{226}}$ nucleus, there are

${\rm{138}}$ neutrons and ${\rm{88}}$ protons

${\rm{138}}$ protons and 88 neutrons

${\rm{226}}$ protons and ${\rm{88}}$ electrons

${\rm{226}}$ neutrons and ${\rm{138}}$ electrons

The energy released in the fission of ${\rm{1}}\,{\rm{Kg}}$ of _92 $_{92}{{\rm{U}}^{235}}$ is (energy per fission ${\rm{ = 200 }}\,{\rm{MeV}}$)

$8.2\,\, \times \,\,{10^{13}}\,\,{\rm{J}}$

$5.1\,\, \times \,\,{10^{26}}\,\,{\rm{eV}}$

$5.1\,\, \times \,\,{10^{26}}\,\,{\rm{J}}$

$8.2\,\, \times \,\,{10^{13}}\,\,{\rm{MeV}}$

The difference between ${{\rm{U}}^{235}}\,\,{\rm{and}}\,\,{{\rm{U}}^{238}}$ atom is that

${{\rm{U}}^{238}}$ contains ${\rm{3}}$ more neutrons

${{\rm{U}}^{238}}$ contains ${\rm{3}}$ more protons

${{\rm{U}}^{238}}$ contains ${\rm{3}}$ protons and ${\rm{3}}$ more electrons

${{\rm{U}}^{238}}$ contains ${\rm{3}}$ more neutrons and ${\rm{3}}$ more electrons

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JEE • PHYSICS • NUCLEI

Nuclei practice · Mixed difficulty

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Practice format and chapter quiz

These sets use single-correct-answer MCQs. They do not cover every JEE Main or JEE Advanced question format and are not full-length mock papers.

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Showing 361-380 of 380 questions

361 Medium

361 of 380

Understanding +4 | -1

The nucleus of atomic mass

A

and atomic number

Z

emits a

\mathrm{\beta }

-particle. The atomic mass and atomic number of the resulting nucleus are

View answer and explanation

Correct option: C

A,Z + 1

Option C is correct because in beta decay, the mass number (A) remains the same, while the atomic number (Z) increases by 1.

362 Easy

362 of 380

Analyzing +4 | -1

The graph of

\ln \left(\frac{R}{R_0}\right)

versus

\ln A

(R=

radius of a nucleus and

A=

its mass number) is:

View answer and explanation

Correct option: A

a straight line

Option A (a straight line) is correct because the relationship between the radius of a nucleus and its mass number is such that the logarithm of their ratio is linearly proportional to the logarithm of the mass number.

363 Medium

363 of 380

Understanding +4 | -1

The volume of the nucleus having a mass number

\mathrm{A}

is directly proportional to

View answer and explanation

Correct option: C

A

Option C (

A

) is correct because the volume of a nucleus is directly proportional to its mass number A.

364 Easy

364 of 380

Understanding +4 | -1

Statement-1: The mass per nucleon in a hydrogen atom is the same as the in an oxygen atom.
Statement-2: The energy released during the formation of nuclei of different atoms from their constituent nuclei is different.

View answer and explanation

Correct option: D

Statement-1 is false, Statement-2 is true

Option D is correct because the mass per nucleon is different for hydrogen and oxygen due to different binding energies, and the energy released during nuclei formation varies.

365 Medium

365 of 380

Understanding +4 | -1

Consider two nuclei of the same radioactive nuclide. One of the nuclei was created in a supernova explosion

\mathrm{5}\,\,\,\mathrm{billion}\,\,\mathrm{years}

ago. The probability of decay during the next time is

View answer and explanation

Correct option: D

Independent of the time of creation

The correct answer is D (Independent of the time of creation) because radioactive decay is a random process and depends only on the decay constant.

366 Medium

366 of 380

Understanding +4 | -1

The fission of

^{235}U

can be triggered by the absorption of slow neutrons by a nucleus. Similarly a slow proton can also be used. This statement is

View answer and explanation

Correct option: B

Wrong

Wrong is correct because fission requires a neutron to initiate the reaction, not a proton due to electrostatic repulsion.

367 Hard

367 of 380

Application +4 | -1

Find out the mass of Uranium required per day to operate 0.95 MW nuclear power plant using

_{92}{U^{235}}

fission.

View answer and explanation

Correct option: A

1 gm

The correct answer is A (1 gm) because the mass of Uranium required is calculated based on the energy released per fission and the power plant's energy output per day.

368 Medium

368 of 380

Understanding +4 | -1

_{88}R{a^{226}}

nucleus, there are

View answer and explanation

Correct option: B

\mathrm{138}

neutrons and

\mathrm{88}

protons

Option B is correct because the number of protons is equal to the atomic number (88), and the number of neutrons is the mass number (226) minus the atomic number (88), which equals 138.

369 Medium

369 of 380

Understanding +4 | -1

According to the quark model, it is possible to build all the hadrons using

View answer and explanation

Correct option: C

\mathrm{3 }\,\mathrm{quarks}

and

\mathrm{3 }\,\mathrm{antiquarks}

Option C (If Assertion is True but the Reason is False) is correct because the assertion about standing waves is correct, but the reason is false as amplitude does depend on position.

370 Medium

370 of 380

Application +4 | -1

Two radioactive sources

A

and

B

of half lives

\mathrm{1}\,\,\mathrm{h }\,\,\mathrm{and}\,\,\mathrm{ 2}\,\,\mathrm{h}

respectively initially contain the same number of radioactive atoms. At the end of two hours, their rates of disintegration are in the ratio of

View answer and explanation

Correct option: C

1:2

Option C (

1:2

) is correct because the ratio of disintegration rates depends on the number of radioactive atoms remaining after two hours, considering their respective half-lives.

371 Medium

371 of 380

Remembering +4 | -1

Which of the following isotopes is normally fissionable

View answer and explanation

Correct option: C

_{92}{U^{235}}

Option C (

_{92}{U^{235}}

) is correct because Uranium-235 is the only naturally occurring isotope that is readily fissionable by slow neutrons.

372 Medium

372 of 380

Application +4 | -1

The energy released in the fission of

\mathrm{1}\,\mathrm{Kg}

of _92

_{92}{\mathrm{U}^{235}}

is (energy per fission

\mathrm{ = 200 }\,\mathrm{MeV}

)

View answer and explanation

Correct option: C

8.2\,\, \times \,\,{10^{13}}\,\,\mathrm{J}

Option C (

8.2 \times 10^{13} J

) is correct because it accurately calculates the energy released from 1 kg of Uranium-235 using the energy per fission and Avogadro's number.

373 Medium

373 of 380

Understanding +4 | -1

The gravitational force between a

{H}

-atom and another particle of mass

m

will be given by Newton's law :

F=G \frac{M \cdot m}{r^2}

, where

r

is (in

{km}

) and

View answer and explanation

Correct option: B

M=m_{\text {proton }}+m_{\text {electron }}-\frac{B}{c^2}(B=13.6 {eV})

Option B (

M=m_{\text {proton }}+m_{\text {electron }}-\frac{B}{c^2}(B=13.6 {eV})

) is correct because the mass of the hydrogen atom is slightly less than the sum of the masses of its constituents due to binding energy.

374 Medium

374 of 380

Understanding +4 | -1

The difference between

{\mathrm{U}^{235}}\,\,\mathrm{and}\,\,{\mathrm{U}^{238}}

atom is that

View answer and explanation

Correct option: D

{\mathrm{U}^{238}}

contains

\mathrm{3}

more neutrons

Option D (

{\mathrm{U}^{238}}

contains

\mathrm{3}

more neutrons) is correct because isotopes of an element differ in the number of neutrons.

375 Medium

375 of 380

Understanding +4 | -1

The half-life of

{ }^{131}I

is 8 days. Given a sample of

{ }^{131} {I}

at time

t=0

, we can assert that

View answer and explanation

Correct option: D

A given nucleus may decay at any time after

t = 0

Option D is correct because radioactive decay is a probabilistic process, and any given nucleus can decay at any time after t=0.

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376 Medium

376 of 380

Understanding +4 | -1

Assertion: In pair annihilation, an electron and position destroy each other and produce

2 \gamma

- rays.

Reason:

2 \gamma

-rays produced will have equal momentum in opposite direction and momentum is conserved.

View answer and explanation

Correct option: B

Both Assertion and Reason are true and Reason is not the correct explanation of Assertion.

Option B (Both Assertion and Reason are true and Reason is not the correct explanation of Assertion) is correct because both the annihilation process and momentum conservation are true, but the reason doesn't directly explain the annihilation.

377 Medium

377 of 380

Application +4 | -1

For radioactive material, the half-life is 10 minutes. If initially, there are 600 number of nuclei, the me taken (in minutes) for the disintegration of 450 nuclei is :

View answer and explanation

Correct option: A

Option A (20) is correct because after 2 half-lives, 450 nuclei will have disintegrated from an initial 600.

378 Medium

378 of 380

Application +4 | -1

Find the maximum energy that a beta particle can have in the following decay

{ }^{176} {Lu} \rightarrow{ }^{176} {Hf}+e+\bar{v} \text {. }

Atomic mass of

{ }^{176} {Lu}

175.942694 \mathrm{u}

and that of

{ }^{176} {Hf}

175.941420 \mathrm{u}

View answer and explanation

Correct option: A

1 . 182 \mathrm{~MeV}

Option A (

1 . 182 \mathrm{~MeV}

) is correct because it is calculated by finding the mass difference between the parent and daughter nuclei and converting it to energy using

E=mc^2

379 Medium

379 of 380

Understanding +4 | -1

After five half lives what will be the fraction of initial substance

View answer and explanation

Correct option: B

{\left( {\frac{1}{2}} \right)^5}

Option B is correct because after each half-life, the amount of substance remaining is halved. After five half-lives, the fraction remaining is (1/2)⁵.

380 Medium

380 of 380

Understanding +4 | -1

The force acting between proton and proton inside the nucleus is

View answer and explanation

Correct option: C

Both

Option C is correct because both the Coulombic (electrostatic) force and the nuclear force act between protons inside the nucleus.

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