Atoms and Nuclei NEET PYQs (1990–2026)

Solved Atoms and Nuclei PYQs

3 recent questions with answers. The full set of 175 is free to practise.

1. NEET 2026HardMass Defect and Binding Energy
   Q1

   Consider the following nuclear reaction:
   
   $${}^{238}U{\to }^{234}Th{+}^{4}He$$
   
   Take masses of ${}^{238}U$, ${}^{234}Th$ and ${}^{4}He$ as 238.050 u, 234.043u and 4.003 u, respectively. The Q value for the reaction, in keV, is:
   
   [Given: $1u=931.5MeV{c}^{-2}$]

   • A3726
   • B3730
   • C3736
   • D3740

   Show answer & solution

   Correct answer: (A)

   Mass defect
   
   $$\Delta m=m_U-\left(m_{Th}+m_{He}\right)=238.050-234.043-4.003=0.004$$
   
   u.
   
   $Q=0.004\times 931.5=3.726$ MeV = 3726 keV.
2. NEET 2026HardRadioactivity – Alpha, Beta, Gamma Decay
   Q2

   Match List I with List II:
   
   List-I (Electromagnetic wave):
   
   A. Microwave,
   
   B. Visible light,
   
   C. Gamma rays,
   
   D. Infra-red rays
   
   List-II (Production):
   
   I. Electrons in atoms emit light when they move from a higher energy level to a lower energy level,
   
   II. Radioactive
   
   decay of nucleus,
   
   III. Vibration of atoms and molecules, IV. Klystron valve or magnetron valve
   
   Choose the correct answer from the options given below:

   • AA-III, B-I, C-II, D-IV
   • BA-III, B-IV, C-I, D-II
   • CA-IV, B-I, C-II, D-III
   • DA-IV, B-III, C-II, D-I

   Show answer & solution

   Correct answer: (C)

   Microwave -- Klystron or magnetron valve (IV); Visible -- electrons
   
   transition (I); Gamma -- radioactive decay (II); Infra-red -- vibration
   
   of atoms/molecules (III). So A-IV, B-I, C-II, D-III.
3. NEET 2026EasyRadius, Velocity and Energy in Bohr's Model
   Q3

   In the first excited state of hydrogen atom, the energy of its electron is $-3.4eV$. The radial distance of the electron from the hydrogen nucleus in this case is approximately:
   
   (Take $1eV=1.6\times 10^{-19}J$, $e=1.6\times 10^{-19}C$ and
   
   $\frac{1}{4\pi {ϵ}_0}=9\times 10^{9}N{m}^2/C^2$)

   • A$2.1\times 10^{-9}m$
   • B$2.1\times 10^{-10}m$
   • C$4.2\times 10^{-10}m$
   • D$4.2\times 10^{-9}m$

   Show answer & solution

   Correct answer: (B)

   Using $\frac{K{Q}^2}{2r}=3.4$ eV:
   
   $$r=\frac{9\times 10^9\times (1.6\times 10^{-19}{)}^2}{2\times 3.4\times 1.6\times 10^{-19}}=2.1176\times 10^{-10}$$
   
   m $\approx 2.1\times 10^{-10}$ m.

Topic-wise question count

Where NEET has asked from Atoms and Nuclei, most frequent first.

• Radioactivity – Alpha, Beta and Gamma Decay49
• Basics of Nucleus29
• Energy Levels and Hydrogen Spectrum22
• Mass Defect and Binding Energy20
• Spectral Series18
• Nuclear Fission and Nuclear Fusion14
• Radius, Velocity and Energy in Bohr’s Model8
• Bohr’s Model of Hydrogen Atom7
• Alpha Particle Scattering Experiment and Rutherford’s Model4
• Bohr's Model of Hydrogen Atom1
• Alpha Particle Scattering / Rutherford's Model1
• Radioactivity – Alpha, Beta, Gamma Decay1
• Radius, Velocity and Energy in Bohr's Model1

Year-wise Atoms and Nuclei questions in NEET

Number of questions from this chapter in each year's paper(s).