Q 11-14-064JEE MainJEE Main 2023 (8 Apr, Shift 1)Easy
The engine of a train moving with speed $10\ \text{m s}^{-1}$ towards a platform sounds a whistle at frequency $400$ Hz. The frequency heard by a passenger inside the train is (Neglect air speed. Speed of sound in air $=330\ \text{m s}^{-1}$)
Answer: (A) $400\ \text{Hz}$
The passenger and the whistle move together, so there is no relative motion and the frequency heard is $400$ Hz.
Solution by Sreeraj P, M.Sc Physics