Question

The wave function of travelling pulse is given by $y=\frac{5}{{\left(4x+6t\right)}^2}$ where x and y are in meter and t is in seconds.the velocity of the pulse is

• A. 1 m/s
• B. 2 m/s
• C. 2.5 m/s
• D. 6 m/s

Answer 1

The correct option is C 2.5 m/s

given that$,$

wave function

$\frac{5}{{\left(4x+6t\right)}^2}$

let $4+6t=m$

thus$,$ differentiate with respect to $t$

$4dx/dt+6=dm/dt$

thus$,$

$y=\frac{5}{m^2}$

$dy/dt=-10/mdm.dt$

$dy/dt=-10m(4dx/dt+6)$

$4dx/dt+6=0$

$dx/dt=-6/4=2.5$

Hence,

option $\left(C\right)$ is correct answer.