Dual Nature, Atoms & Nuclei · JEE Main previous year questions

2023 55 questions

1. Q502023 · 24 Jan 2023 · Shift 1

   Consider the following radioactive decay process $${}_{84}^{218}\mathrm{A}\stackrel{\alpha }{\to }{\mathrm{A}}_1\stackrel{{\beta }^{-}}{\to }{\mathrm{A}}_2\stackrel{\gamma }{\to }{\mathrm{A}}_3\stackrel{\alpha }{\to }{\mathrm{A}}_4\stackrel{{\beta }^{+}}{\to }{\mathrm{A}}_5\stackrel{\gamma }{\to }{\mathrm{A}}_6$$ The mass number and the atomic number of ${\mathrm{A}}_6$ are given by :

   1. A.210 and 84
   2. B.210 and 80
   3. C.211 and 80
   4. D.210 and 82
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   Answer: B

2. Q602023 · 24 Jan 2023 · Shift 1· Numerical answer

   Assume that protons and neutrons have equal masses. Mass of a nucleon is $1.6\times 10^{-27}\mathrm{kg}$ and radius of nucleus is $1.5\times 10^{-15}{\mathrm{A}}^{1/3}\mathrm{m}$. The approximate ratio of the nuclear density and water density is $n\times 10^{13}$. The value of $n$ is ____.

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   Answer: 11

3. Q352023 · 24 Jan 2023 · Shift 2

   An $\alpha$-particle, a proton and an electron have the same kinetic energy. Which one of the following is correct in case of their de-Broglie wavelength:

   1. A.${\lambda }_{\alpha }>{\lambda }_p<{\lambda }_e$
   2. B.${\lambda }_{\alpha }>{\lambda }_p>{\lambda }_e$
   3. C.${\lambda }_{\alpha }={\lambda }_p={\lambda }_e$
   4. D.${\lambda }_{\alpha }<{\lambda }_p<{\lambda }_e$
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   Answer: D

4. Q462023 · 24 Jan 2023 · Shift 2

   A photon is emitted in transition from n = 4 to n = 1 level in hydrogen atom. The corresponding wavelength for this transition is (given, $\mathrm{h}=4\times 10^{-15}\mathrm{eVs}$) :

   1. A.$99.3\mathrm{nm}$
   2. B.$94.1\mathrm{nm}$
   3. C.$974\mathrm{nm}$
   4. D.$941\mathrm{nm}$
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   Answer: B

5. Q532023 · 24 Jan 2023 · Shift 2· Numerical answer

   The energy released per fission of nucleus of ${}^{240}\mathrm{X}$ is 200 MeV. The energy released if all the atoms in 120g of pure ${}^{240}\mathrm{X}$ undergo fission is _________ $\times 10^{25}\mathrm{MeV}$. (Given ${\mathrm{N}}_{\mathrm{A}}=6\times 10^{23}$)

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   Answer: 6