Question

An air column in a pipe, which is closed at one end will be in resonance with a vibrating tuning fork of frequency 264 Hz, What is the length of the column if it is in cm? (speed of sound in air = 330 m/s) 

(A) 62.50 

(B) 15.62 

(C) 125 

(D) 93.75

Answer 1

The correct option is (D) 93.75.

Explanation:

For closed organ pipe, f = n (V / 4ℓ) where n = 1, 3, 5 ----- 

∴ ℓ = (nV / 4f) 

∴ ℓ = η{(330) / (4 × 264)} = 0.3125 η 

∴ ℓ = 0.3125 × 3m and 0.3125 × 5 m ---- n = 3 and n = 5 

∴ ℓ = 0.9375 m and 1.5625 m 

∴ ℓ = 93.75 cm