question_answer

Tuning fork \[{{F}_{1}}\] has a frequency of 256 Hz and it is observed to produce 6 beats/second with another tuning fork \[{{F}_{2}}\]. When \[{{F}_{2}}\] is loaded with wax, it still produces 6 beats/second with \[{{F}_{1}}\]. The frequency of \[{{F}_{2}}\] before loading was [MP PET 1990]

A)            253 Hz                                     

B)            262 Hz

C)            250 Hz                                     

D)            259 Hz

Correct Answer: B

Solution :

           nA = Known frequency = 256 Hz, nB = ? x = 6 bps, which remains the same after loading. Unknown tuning fork F2 is loaded so nB¯ Hence nA ? nB¯  = x        ... (i)                Wrong              nB¯  ? nA = x        ... (ii)             Correct Þ nB = nA + x = 256 + 6 = 262 Hz.