Question

Three resonant frequencies of a string are 90, 150 and 210 Hz. (a) Find the highest possible fundamental frequency of vibration of this string. (b) Which harmonics of the fundamental are the given frequencies ? (c) Which overtones are these frequencies ? (d) If the length of the string is 80 cm, what would be the speed of a transverse wave on this string ?
A. `45 m//s`
B. `75 m//s`
C. `48 m//s`
D. `80 m//s`

Answer 1

Correct Answer - C
These are multiple of 30 Hz. Hence, fundamental
frequency
`f_(0) = 30Hz`
Now, `f_(0) = v/(2l)`
`:. v=2f_(0)l `
`=2xx 30 xx 0.8`
`=48 m//s` .