A tuning fork of frequency 480 Hz produces 10 beats per second when sounded with a vibrating sonometer string. What must have been the frequency of the string if a slight increase in tension produces lesser beats per second than before
If suppose ns= frequency of string =12l√Tm
nf= Frequency of tuning fork =480 Hz
x= Beats heard per second =10
as tension T increases, so ns increases (↑)
Also it is given that number of beats per sec decreases (i.e. x↓)
Hence ns↑−nf =x↓ ....(i)→ Wrong
nf−ns↑ =x↓ ....(ii)→ Correct
⇒ ns=nf−x=480−10=470 Hz.