A train with a whistle that emits a note of frequency 800 Hz is approaching an observer at speed of 60 m s-1, the frequency of note heard by observer is {{}}

A train with a whistle that emits a note of frequency 800 Hz is approa

1.	A train with a whistle that emits a note of frequency 800 Hz is approaching an observer at speed of 60 m s-1, the frequency of note heard by observer is {{}}
A.	978 Hz
B.	980 Hz
C.	950 Hz
D.	900 Hz
Answer» B. 980 Hz