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MHT CET 2026 (19 May, Shift 1) · Bohr Model: Orbits, Speed & Angular Momentum

Bohr Model: Orbits, Speed & Angular Momentum question from MHT CET 2026 (19 May, Shift 1)

Q21MHT CET 2026 · 19 MAY · SHIFT 1Medium

Bohr Model: Orbits, Speed & Angular Momentum

The moment of inertia of the electron moving in the second Bohr orbit of a hydrogen atom is [mm = mass of electron, hh = Planck's constant, ee = charge on electron, ε0\varepsilon_0 = permittivity of free space]

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Answer: (b)

  1. rn=ε0h2n2πme2r_n = \frac{\varepsilon_0 h^2 n^2}{\pi m e^2}, so r2=4ε0h2πme2r_2 = \frac{4\varepsilon_0 h^2}{\pi m e^2}
  2. I=mr22=m⋅16ε02h4π2m2e4I = m r_2^2 = m\cdot\frac{16\varepsilon_0^2 h^4}{\pi^2 m^2 e^4}
  3. I=16ε02h4π2me4I = \frac{16\varepsilon_0^2 h^4}{\pi^2 m e^4}
  4. So the answer is (b).
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