Question

The displacement of a particle in string stretched in X direction is represented by y. Among the following expressions for y, those describing wave motions are

• A. cos($k^3$ $x^3$ - ${\omega }^3$ $t^3$)
• B. $k^2$ $x^2$ - ${\omega }^2$ $t^2$
• C. cos (kx + $\omega$ t)
• D. cos($k^2$ $x^2$ - ${\omega }^2$ $t^2$)

Answer 1

The correct option is C

cos (kx + $\omega$ t)

y = cos (kx + $\omega$ t) represents wave motion , because they satisfy the wave equation

$\frac{{\partial }^{2}y}{\partial t^2}$ = $v^2$$\frac{{\partial }^{2}y}{\partial x^2}$