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Nuclei · Question 10

JEE Main 2026 (Online) 24th January Evening ShiftMCQMedium📈 Topic in 26% papers+4−1
1

The binding energies for the following nuclear reactions are expressed in MeV. 2He3 + 0n1 2He4 + 20 MeV 2He4 + 0n1 2He5 - 0.9 MeV If X3, X4, X5 denote the stability of 2He3, 2He4 and 2He5, respectively, then the correct order is :

  1. X4 > X5 > X3
  2. X4 < X5 < X3
  3. X4 > X5 < X3
  4. X4 = X5 = X3

Answer

(1) X4 > X5 > X3

Solution

Stability of a nucleus is measured by its binding energy per nucleon.

Reaction 1 releases 20 MeV: BE(He4) = BE(He3) + 20 MeV

Reaction 2 absorbs 0.9 MeV: BE(He5) = BE(He4) - 0.9 MeV

Adding a neutron to He4 lowers the total binding energy, BEA of He5 is less than that of He4 X4 > X5

From the two equations: BE(He5) = BE(He3) + 19.1 MeV, i.e. He5 gains about 19 MeV for only 2 extra nucleons.

Taking BE(He4) = 28.3 MeV: BE(He3) = 8.3 MeV, BE(He5) = 27.4 MeV

BEA: He3: 8.33 2.8 MeV, He4: 28.34 7.1 MeV, He5: 27.45 5.5 MeV

X5 > X3

X4 > X5 > X3

Answer: (1)

JEE Main 2026 (Online) 24th January Evening Shift

Keep practising — Nuclei

2

Which of the following pair of nuclei are isobars of the element?

  1. 31H and 32He
  2. 19880Hg and 19779Au
  3. 21H and 31H
  4. 23692U and 23892U
JEE Main 2026 (Online) 23rd January Evening Shift
3

The average energy released per fission for the nucleus of 23592U is 190 MeV. When all the atoms of 47 g pure 23592U undergo fission process, the energy released is 1023 MeV. The value of is . (Avogadro Number = 6 1023 per mole)

JEE Main 2026 (Online) 23rd January Evening Shift
4

The minimum frequency of photon required to break a particle of mass 15.348 amu into 4 particles is kHz. [mass of He nucleus = 4.002 amu, 1 amu = 1.66 10-27 kg, h = 6.6 10-34 J s and c = 3 108 m/s]

  1. 14.94 1020
  2. 9 1019
  3. 9 1020
  4. 14.94 1019
JEE Main 2026 (Online) 22nd January Morning Shift
5

For a nucleus of mass number A and radius R, the mass density of nucleus can be represented as

  1. A 23
  2. Independent of A
  3. A3
  4. A 13
JEE Main 2025 (Online) 8th April Evening Shift
6

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below :

  1. (A) is correct but (R) is not correct
  2. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
  3. (A) is not correct but (R) is correct
  4. Both (A) and (R) are correct and (R) is the correct explanation of (A)
JEE Main 2025 (Online) 7th April Evening Shift
7

A radioactive material P first decays into Q and then Q decays to non-radioactive material R. Which of the following figure represents time dependent mass of P, Q and R ?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2025 (Online) 4th April Evening Shift
8

Match the LIST-I with LIST-II Choose the correct answer from the options given below:

  1. A-II, B-I, C-III, D-IV
  2. A-III, B-I, C-II, D-IV
  3. A-III, B-I, C-IV, D-II
  4. A-II, B-I, C-IV, D-III
JEE Main 2025 (Online) 3rd April Morning Shift
9

Energy released when two deuterons (1H2 ) fuse to form a helium nucleus (2He4 ) is : (Given : Binding energy per nucleon of 1H2 = 1.1 MeV and binding energy per nucleon of 2He4 = 7.0 MeV)

  1. 26.8 MeV
  2. 8.1 MeV
  3. 23.6 MeV
  4. 5.9 MeV
JEE Main 2025 (Online) 2nd April Evening Shift
10

Choose the correct nuclear process from the below options [p : proton, n : neutron, e- : electron, e+ : positron, : neutrino, : antineutrino]

  1. n p + e+ +
  2. n p + e- +
  3. n p + e+ +
  4. n p + e- +
JEE Main 2025 (Online) 28th January Morning Shift

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