Write difinition of wave speed and derive `v = (omega )/(k).`

Explanation

Wave speed : "The distance covered by wave in unit time is called wave speed".
Its unit is `m/s` and dimensional formula is `[M^(0) L ^(1) T ^(-1)].`
`lamda ` is the distance covered by wave in time T.
`therefore ` Wave speed `v= ("distance covered"(lamda))/("time")(T)`
`v = (lamda )/(T)`
but ` 1/T = v ` frequency
`therefore v = v lamda`
`therefore v = 2pi v xx (lamda )/(2pi )`
`therefore v = (omega )/(k) [because 2pi v = omega, (lamda )/(2pi ) = (1)/(k)]`