Q 11-14-089JEE MainJEE Main 2021 (26 Feb, Shift 1)Easy
The mass per unit length of a uniform wire is $0.135$ g cm$^{-1}$. A transverse wave of the form $y = -0.21\sin(x + 30t)$ is produced in it, where $x$ is in meter and $t$ is in second. Then, the expected value of tension in the wire is $x\times10^{-2}$ N. Value of $x$ is ______ (Round-off to the nearest integer)
Numerical value type. Enter your answer.
Answer: 1215
$\mu = 0.135$ g cm$^{-1}$ $= 0.0135$ kg m$^{-1}$.
Wave speed $v = \dfrac{\omega}{k} = \dfrac{30}{1} = 30$ m s$^{-1}$.
$$T = \mu v^2 = 0.0135\times900 = 12.15\ \text{N} = 1215\times10^{-2}\ \text{N}$$
Solution by Sreeraj P, M.Sc Physics