Question

A tuning fork sounded together with a tuning fork of frequency 256 emits two beats. On loading the tuning fork of frequency 256, the number of beats heard are 1 per second. The frequency of tuning fork is

• A. 257
• B. 258
• C. 256
• D. 254

Answer 1

Answer: (D)

254

Answer 2

n_A = Known frequency = 256, n_B = ?

x = 2 bps, which is decreasing after loading (i.e. x↓) known tuning fork is loaded so n_A↓

Hence n_A↓ – n_B = x↓ ... (i) Correct

n_B – n_A↓ = x↓ ... (ii) Wrong

⇒ n_B = n_A – x = 256 – 2 = 254 Hz.