The difference in angular momentum associated with the electron in th…

The correct answer is Option (2) → \( \displaystyle\frac{h}{2\pi} \)

Bohr’s quantisation condition: the angular momentum of the electron in the nth orbit is an integral multiple of \( h/2\pi \).

    \( \displaystyle L_n = \frac{nh}{2\pi} \)

For two successive orbits, n and n + 1:

    \( \displaystyle L_{n+1} - L_n = \frac{(n + 1)h}{2\pi} - \frac{nh}{2\pi} \)

    \( \displaystyle L_{n+1} - L_n = \frac{h}{2\pi} \)

Note: This question is from NCERT (2026-27). NTA sets numerical questions from NCERT too, so do not ignore NCERT while practising numericals.

NCERT (2026-27):
Bohr Model of the Hydrogen Atom – “… (ii) Bohr’s second postulate defines these stable orbits. This postulate states that the electron revolves around the nucleus only in those orbits for which the angular momentum is some integral multiple of \( h/2\pi \) where \( h \) is the Planck’s constant (\( = 6.6\times10^{-34}\,\mathrm{J\,s} \)). Thus the angular momentum (\( L \)) of the orbiting electron is quantised. That is

    \( \displaystyle L = nh/2\pi \qquad (12.5) \)”