Question

A string of length 1.5 m with its two ends clamped is vibrating in fundamental mode. Amplitude at the centre of the string is 4 mm. Minimum distance between the two points having amplitude 2 mm is:
A. `1m`
B. `75cm`
C. `60cm`
D. `50cm`

Answer 1

Correct Answer - B
Equation of standing wave
`y=Asinkxcosomegat`
`y=A` as amplitude is 2A
`A=2Asinkx`
`(2pi)/(lamda)x=(pi)/(6)impliesx_1=(1)/(4)m`
and `(2pi)/(lamda).x=(pi)/(2)+(pi)/(3)`
`impliesx_1=1.25mimpliesx_2-x_1=1m`