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

nA = Known frequency = 256, nB = ?x = 2 bps, which is decreasing after loading (i.e. x↓) known tuning fork is loaded so nA↓ Hence nA↓ – nB = x↓        ... (i)       →       Correct            nB  – nA↓ = x↓      ... (ii)       →       Wrong⇒ nB = nA – x = 256 – 2 = 254 Hz.