Question

A string of mass $2.50kg$ is under a tension of $200N$ . The length of the stretched string is $20m$ . if the transverse jerk is struck at one end of the string, how long does the disturbance take to reach the other end?

• A. $0.50s$
• B. $0.20s$
• C. $0.10s$
• D. $0.40s$

Answer 1

Answer: (A)

Velocity of transverse wave
$v=\sqrt{\frac{T}{\mu }}$
where, T = tension in the string = 200 N
μ= mass per unit length
$=\frac{\text{Mass}}{\text{Length}}=\frac{2\cdot 50}{20}=0\cdot 125\text{kg/m}$
$v=\sqrt{\frac{200}{0\cdot 125}}=\sqrt{1600}=40\text{m/s}$
Time taken by the disturbance to reach the other end
$t=\frac{l}{v}=\frac{20}{40}=0\cdot 50\text{s}$