Question

A string of length l hangs freely from a rigid support. The time required by a transverse pulse to travel from bottom to half length of the string is

• A. $\sqrt{lg}$
• B. $\sqrt\frac{l}{g}$
• C. $2\sqrt\frac{l}{g}$
• D. $2\sqrt{l}{g}$

Answer 1

Answer: (C)

$2\sqrt\frac{l}{g}$

Answer 2

$f =\frac{ v }{2 l }=\frac{\sqrt{\frac{ T }{ m / l }}}{2 l }=\frac{1}{2}$ $\sqrt{\frac{ T }{ ml }}=\frac{1}{2} \sqrt{\frac{ mg }{ ml }}$ $=\frac{1}{2} \sqrt{\frac{ g }{1}}$ $\text { time taken }=\frac{1}{ f }=2 \sqrt{\frac{1}{ g }}$