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Nuclei

JEE Mains Physics. Try each one first, then open its answer.

Top 10 JEE Mains PYQs to practise first

The questions and kinds of question asked most often come first. Each one says how often and in which papers.

  1. Question 1

    This type asked 7 times: 14 Jun 2022, 26 Jul 2022, 8 Apr 2023, 27 Jan 2024, 2 Apr 2025, 4 Apr 2026 S1, 6 Apr 2026 S2. This one: 6 Apr 2026 S2 See all 7 of this type

    16
    The energy released if two  12H\ _{1}^{2}H (deuterium) atoms are combined to form  24He\ _{2}^{4}He is ____\_\_\_\_ MeV. (Take binding energies per nucleon of  12H\ _{1}^{2}H and  24He\ _{2}^{4}He as 1.1 MeV and 7.2 MeV, respectively).

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  2. Question 2

    This type asked 7 times: 2021 Paper 20, 29 Jun 2022, 27 Jul 2022, 28 Jul 2022, 29 Jan 2023, 10 Apr 2023, 15 Apr 2023. This one: 15 Apr 2023 See all 7 of this type

    5
    The half-life of a radioactive nucleus is 5 years, the fraction of the original sample that would decay in 15 years is:

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  3. Question 3

    This type asked 6 times: 25 Jan 2023, 11 Apr 2023, 31 Jan 2024, 1 Feb 2024, 28 Jan 2026 S1, 28 Jan 2026 S2. This one: 28 Jan 2026 S2 See all 6 of this type

    1
    A nucleus has mass number α\alpha and radius RαR_{\alpha} Another nucleus has mass number β\beta and radius RβR_{\beta}. If β=8α\beta= 8\alpha then Rα/RβR_{\alpha}/R_{\beta} is :

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  4. Question 4

    This type asked 5 times: 1 Feb 2023, 27 Jan 2024, 8 Apr 2024, 2 Apr 2026 S2, 5 Apr 2026 S2. This one: 5 Apr 2026 S2 See all 5 of this type

    19
    Assuming the experimental mass of  612C\ _{6}^{12}C as 12 u , the mass defect of  612C\ _{6}^{12}C atom is ____\_\_\_\_ MeV/c2MeV/c^{2}. (Mass of proton =1.00727u= 1.00727u. mass of neutron =1.00866u,1u=931.5MeV/c2= 1.00866u,1u = 931.5MeV/c^{2} and c is the speed of the light in vacuum.)

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  5. Question 5

    This type asked 5 times: 26 Jul 2022, 29 Jul 2022, 25 Jan 2023, 30 Jan 2023, 7 Apr 2025. This one: 7 Apr 2025 See all 5 of this type

    77
    Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : The density of the copper ( 2964Cu)\left( \ _{29}^{64}Cu \right) nucleus is greater than that of the carbon ( 612C)\left( \ _{6}^{12}C \right) nucleus. Reason (R) : The nucleus of mass number A has a radius proportional to A1/3A^{1/3}. In the light of the above statements, choose the most appropriate answer from the options given below:

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  6. Question 6

    This type asked 5 times: 2021 Paper 3, 14 Jun 2022, 29 Jul 2022, 29 Jan 2023, 23 Jan 2025. This one: 23 Jan 2025 See all 5 of this type

    6
    A radioactive nucleus n2n_{2} has 3 times the decay constant as compared to the decay constant of another radioactive nucleus n1n_{1}. If initial number of both nuclei are the same, what is the ratio of number of nuclei of n2n_{2} to the number of nuclei of n1n_{1}, after one half-life of n1n_{1} ?

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  7. Question 7

    This type asked 5 times: 2021 Paper 12, 2021 Paper 15, 27 Jul 2022, 28 Jul 2022, 8 Apr 2023. This one: 8 Apr 2023 See all 5 of this type

    96
    A radio-active material is reduced to 1/81/8 of its original amount in 3 days. If 8×10−3 kg8 \times10^{- 3}\text{ }kg of the material is left after 5 days. The initial amount of the material is

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  8. Question 8

    This type asked 4 times: 2021 Paper 9, 2021 Paper 11, 26 Jun 2022, 30 Jan 2023. This one: 30 Jan 2023 See all 4 of this type

    114
    A radioactive nucleus decays by two different process. The half-life of the first process is 5 minutes and that of the second process is 30 s30\text{ }s. The effective half-life of the nucleus is calculated to be α11 s\frac{\alpha}{11}\text{ }s. The value of α\alpha is______

  9. Question 9

    This type asked 3 times: 2021 Paper 6, 2021 Paper 14, 10 Apr 2023. This one: 10 Apr 2023 See all 3 of this type

    27
    The decay constant for a radioactive nuclide is 1.5×10−5 s−11.5 \times10^{- 5}{\text{ }s}^{- 1}. Atomic mass of the substance is 60 g60\text{ }g mole  −1,( NA=6×1023)\ ^{- 1},\left( {\text{ }N}_{A}= 6 \times10^{23} \right). The activity of 1.0μg1.0\mu g of the substance is___ ×1010 Bq\times10^{10}\text{ }Bq.

  10. Question 10

    This type asked 3 times: 26 Jun 2022, 29 Jun 2022, 29 Jan 2023. This one: 29 Jan 2023 See all 3 of this type

    30
    A radioactive element  92242X\ _{92}^{242}X emits two α\alpha-particles, one electron and two positrons. The product nucleus is represented by  P234Y\ _{P}^{234}Y. The value of PP is