A vibrating string of certain length \( l \) under a tension \( T \) resonates with a mode corresponding to the first overtone
\( \mathrm{P} \) (third harmonic) of an air column of length \( 75 \mathrm{~cm} \) inside a
W tube closed at one end. The string also generates 4 beats per second when excited along with a tuning fork of frequency \( n \). Now when the tension of the string is slightly increased the number of beats reduces to 2 per second. Assuming the velocity of sound in air to be \( 340 \mathrm{~m} / \mathrm{s} \), the frequency \( n \) of the tuning fork in \( \mathrm{Hz} \) is
[IIT-JEE 2008]
(a) 344
(b) 336
(c) \( 117.3 \)
(d) \( 109.3 \)
ЁЯУ▓PW App Link - https://bit.ly/YTAI_PWAP
ЁЯМРPW Website - https://www.pw.live
0