Question:
A train is moving on a straight track with speed $20 \mathrm{~ms}^{-1}$. It is blowing its whistle at the frequency of $1000 \mathrm{~Hz}$. The percentage change in the frequency heard by a person standing near the track as the train passes him is (speed of sound $=320 \mathrm{~ms}^{-1}$ ) close to :-
Correct Option: , 4
Solution: