Question

Assertion : Rydberg’s constant varies with the mass number of a given element.
Reason : The reduced mass of the electron is dependent on the mass of the nucleus only.

• A. If both A and R are true, and R is a correct explanation of the A
• B. If both A and R are true, but R is not a correct explanation of the A
• C. If A is true, but R is false
• D. If both A and R are false

Answer 1

Answer: (D)

We know that the Rydberg constant is given by $R = \frac{13.6e\,V}{hc}$,
which is independent of the mass number of an element.
The electron does not have a reduced mass. It is defined only for a system of masses.