If two tuning forks A and B are sounded together, they produce 4 beats per second. A is then slightly loaded with wax, they produce 2 beats when sounded again. The frequency of A is 256. The frequency of B will be

nA = Known frequency = 256 Hz, nB = ?x = 4 bps, which is decreasing after loading (i.e. x↓) also known tuning fork is loaded so nA↓Hence nA↓ – nB  = x↓        ... (i)       →      Correct            nB  – nA↓ = x↓        ... (ii)      →      Wrong⇒ nB = nA – x = 256 – 4 = 252 Hz.