A set of 24 tuning forks are so arranged that each gives 6 beats/s with the previous one. If the frequency of the last tuning fork is double that of the first, frequency of the second tuning fork is :

Options

A. ` 138` Hz
B. 132 Hz
C. 144 Hz
D. 276 Hz

Answer

C

Explanation

The frequencies of tuning forks are the terms of an AP whose common difference is 6.
` therefore " " l=a +(n-1) d`
` " " 2a= a +(24-1) xx 6`
` " "a = 23 xx 6`
` " " = 138`
` therefore` Second frequency = 138 +6
` " "= 144 Hz`