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Nuclei

JEE Main 2025 (Online) 8th April Evening ShiftMCQEasy📈 Topic in 10% papers+4−1
Ques. 1JEE Main 2025, 8 April (Evening Shift)

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

Answer

(2) Independent of A

Solution

Nuclear radius: R = R0A 13; mass A m (m = mass of a nucleon)

= Am 43 R3 = Am 43 R03 A = 3m4 R03

the nuclear mass density is independent of A.

Answer: (2)

Keep practising — Nuclei

Ques. 2JEE Main 2025, 7 April (Evening Shift)

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)
Ques. 3JEE Main 2025, 4 April (Evening Shift)

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]
Ques. 4JEE Main 2025, 3 April (Morning Shift)

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
Ques. 5JEE Main 2025, 2 April (Evening Shift)

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
Ques. 6JEE Main 2025, 28 January (Morning Shift)

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- +
Ques. 7JEE Main 2025, 23 January (Morning Shift)

A radioactive nucleus n2 has 3 times the decay constant as compared to the decay constant of another radioactive nucleus n1. If initial number of both nuclei are the same, what is the ratio of number of nuclei of n2 to the number of nuclei of n1, after one half-life of n1 ?

  1. 1/4
  2. 1/8
  3. 4
  4. 8
Ques. 8JEE Main 2025, 23 January (Evening Shift)

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 correct answer from the options given below :

  1. (A) is true but (R) is false
  2. Both (A) and (R) are true and (R) is the correct explanation of (A)
  3. (A) is false but (R) is true
  4. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
Ques. 9JEE Main 2024, 9 April (Morning Shift)

The energy equivalent of 1 g of substance is :

  1. 5.6 1026 MeV
  2. 5.6 1012 MeV
  3. 5.6 eV
  4. 11.2 1024 MeV
Ques. 10JEE Main 2024, 9 April (Morning Shift)

A star has 100\% helium composition. It starts to convert three 4He into one 12C via triple alpha process as 4He + 4He + 4He 12C + Q. The mass of the star is 2.0 1032 kg and it generates energy at the rate of 5.808 1030 W. The rate of converting these 4He to 12C is n 1042 s-1, where n is . [Take, mass of 4He = 4.0026 u, mass of 12C = 12 u]

Ques. 11JEE Main 2024, 9 April (Evening Shift)

The energy released in the fusion of 2 kg of hydrogen deep in the sun is EH and the energy released in the fission of 2 kg of 235U is EU. The ratio EHEU is approximately: (Consider the fusion reaction as 4 11H + 2e- 24He + 2 + 6 + 26.7 MeV, energy released in the fission reaction of 235U is 200 MeV per fission nucleus and NA = 6.023 1023)

  1. 7.62
  2. 25.6
  3. 9.13
  4. 15.04

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