Question

An observer is moving away from a source at rest. The pitch of the note heard by the observer is less because :

• A. the pitch of the source decreases
• B. the velocity of sound in air increases
• C. wave length of the wave becomes small
• D. wavelength of the wave remains unchanged but observer receives less number of waves

Answer 1

The correct option is D wavelength of the wave remains unchanged but observer receives less number of waves

Frequency heard by the observer will decrease, due to which less number of wave will reach to the observer,

$f=(\frac{V-Vo}{V})f_o$