The wave speed in string is given by vw=μT, where, T is tension and μ=lm is linear mass density.
Putting the values, we have
⇒60=10×10−3T×0.5
⇒T=0.5(60)2×10−2=72N
The Young's modulus is given by Y=AΔlFl, here, A is area.
From above the extension of the wire is Δl=AYTl=2×10−6×1.2×101172×0.5=2472×5×10−5=15×10−5m.
Hence, the value of x=15.