Question

When the listener and the source of sound are moving toward each other with unequal velocities, and if the actual and the apparent frequencies of the sound are $\text{f}$ and $\text{f *}$ respectively, then:

• A. $\text{f *}=\text{f}$
• B. $\text{f *}<\text{f}$
• C. $\text{f *}>\text{f}$
• D. Data insufficient

Answer 1

The correct option is C $\text{f *}>\text{f}$

When both the source and the listener are moving toward each other with unequal velocities, the distance between them would decrease with time. As a result, the sound feels louder to the listener as they approach each other. This is because the apparent frequency is greater than the actual frequency of the sound, i.e. $\text{f *}>\text{f}$