Question

A source emits a sound of a frequency of $400Hz$ , but the listener hears it $390Hz$ . Then

• A. The listener is moving towards the source
• B. The source is moving towards the listener
• C. The listener is moving away from the source
• D. The listener has a defective ear

Answer 1

Answer: (C)

Real frequency $\nu =400Hz$
Apparent frequency ${\nu }^{\prime }=390Hz$
${\nu }^{\prime }<\nu$
So, the distance between the source and listener increases or the listener is going away from the source.