Question
A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. The lowest resonant frequency for this strings is
-
155 Hz
-
205 Hz
-
10.5 Hz
-
105 Hz
Solution
D.
105 Hz
Given l = 75 cm, f1 = 420 Hz and f2 = 315 Hz
As two consecutive resonant frequencies for a string fixed at both ends will be +
Thus, lowest resonant frequency of a string is 105 Hz.
