Sol. . m = mass per unit length = 1.2 * 10–4 kg/mt
Y = (0.02m) sin [(1.0 m–1)x + (30 s–1)t]
Here, k = 1 m–1 = 2π/λ
ω = 30 s–1 = 2πf
∴ velocity of the wave in the stretched string
v = λf = ω/k = 30/I = 30 m/s
⇒ v = √T /m ⇒ 30 √(T /1.2) *10-4N)
⇒ T = 10.8 * 10–2 N ⇒ T = 1.08 * 10–1 Newton.