Question

Suppose frequency of emitted photon is $f_0$ when the electron of a stationary hydrogen atom jumps from a higher state $m$ to a lower state $n$. If the atom is moving with a velocity $V\left(\text{<< c}\right)$ and emits a photon of frequency $f$ during the same transition, then which of the following statements are possible?

• A. $f$ may be equal to $f_0$
• B. $f$ may be greater than $f_0$
• C. $f$ may be less than $f_0$
• D. $f$ cannot be equal to $f_0$

Answer 1

Answer: (A), (B), (C)

The correct options are
A $f$ may be equal to $f_0$
B $f$ may be greater than $f_0$
C $f$ may be less than $f_0$

The frequency of an electron does change. The frequency of an electron is proportional to $\frac{z^2}{n^3}$, where $n$ is orbit and $z$ is atomic no. When an electron jumps, the value of $n$ changes and frequency changes accordingly.

So, $\left(a\right),\left(b\right),\left(c\right)$ are correct options.