Correct Answer - A
m=mass per unit length `=1.2xx10^-4kg/m`
`Y=(0.02m)sin`
`[1.0m^-1]x(30s^-1)t]`
Here `k=1m^-1=(2pi)/lamda`
`=w=30s^-1=2pif`
`:.` velocity of the wave in the stretched string
`v=lamdaf=omega/k=30/I`
`=30m/s`
`rarr v=(T/m)`
`rarr 30=sqrt((T/1.2xx10^-4N))`
`rarr T=10.8x10^-2N`
`rarr T=0.08Newton`