A string of length `20 cm` and linear mass density `0.40 g//cm` is fixed at both ends and is kept under a tension of `16 N.A` wave pulse is produced at `t=0` nearj an end as shown in figure which travels towards the other end.
when will the string have the shape shown in the figure again? `(inxx10^(-2)s)`

Answer

A, B

Explanation

`v = sqrt(T/mu) = sqrt((16)/((0.4 xx 10^(-3))//(10^-2))) = 20 m//s`
(a) `t = d/v = (2l)/v = (0.4m)/20`
`=0.02s `
`(b) At half the time pulse is at other end and it gets
a phase difference of `pi`. Hence, the shape is as
shown below.
` (##DCP_V03_C18_E01_042_S01.png" width="80%"> .