MCQ
$A$ source $S$ of frequency $f_0$ and an observer $O$, moving with speeds $v_1$ and $v_2$ respectively, are movinng away from each other. When they are separated by distance a $(t =0)$, a pulse is emitted by the source. This pulse is received by $O$ at time $t_1$ then $t_1$, is equal to
- A$\frac{a}{{{v_s} + {v_2}}}$
- B$\frac{a}{{{v_1} + {v_s}}}$
- ✓$\frac{a}{{{v_s} - {v_2}}}$
- D$\frac{a}{{{v_1} + {v_2} + {v_s}}}$
