Question

Identify the false statement among the following.

• A. Heisenberg's principle is contradictory to Bohr's theory
• B. Planck's quantum theory is taken as the basis for Bohr's theory
• C. Splitting up of spectral lines in presence of external magnetic field is due to the existence of sub shells
• D. Both A and C

Answer 1

The correct option is C Splitting up of spectral lines in presence of external magnetic field is due to the existence of sub shells

1. Option A is true. Bohr gave the theory of fixed orbits, which was contradictory to Heisenberg’s theory.
2. Option B is true. The electrons can only orbit stably, without radiating, in certain orbits (called by Bohr the "stationary orbits") at a certain discrete set of distances from the nucleus. These orbits are associated with definite energies and are also called energy shells or energy levels. In these orbits, the electron's acceleration does not result in radiation and energy loss as required by classical electromagnetics. The Bohr model of an atom was based upon Planck's quantum theory of radiation.
3. Option C is false. Bohr theory could not explain the Zeeman effect. In presence of magnetic field, each spectral line gets split up into fine lines, the phenomenon, is known as Zeeman effect.

Hence, C is the answer.