Question

An air column in a pipe, which is closed at one end, will be in resonance with a vibrating tuning fork of frequency 256 Hz, if the length of the column in centimeter is (velocity of sound in air = 340 m/s)

(a) 21.25 

(b) 125 

(c) 62.50 

(d) 33.2

Answer 1

Correct answer is (d) 33.2

\(f = \frac{v}{4L}\)

⇒ L = \(\frac {v}{4f}\) 

= \(\frac{34000}{4 \times 256}\) = 33.2 cm