Question

In doppler effect

• A. only frequency changes
• B. both intensity and frequency change
• C. only speed changes.
• D. both speed and frequency change

Answer 1

The correct option is A only frequency changes

Doppler effect is change in frequency or wavelength of a wave for an observer moving relative to source. The Doppler shift in frequency is given by:
$f^{\prime }=f\frac{v+v_o}{v-v_s}$
where $f=$ frequency of source
$f^{\prime }=$ Doppler frequency
$v=$ speed of wave
$v_o=$ speed of observer
$v_s=$ speed of source