Question

A wave travels at speed 4.0 m/s. Its wavelength is 22 cm. What is the frequency of the wave?

Answer 1

Given data:

     wave length (λ) = 22 cm = 0.22 m,

     speed of wave length(v) = 4 m/s ,  

determine the frequency (f)  = ?

 We know that ,

          wave length and frequency of light are closely related. The higher the frequency, shorter is the wavelength and vice-versa.

          Mathematically, λ = v/f             -------------------- (i)

                where,  λ = wave length (m)

                             v = speed of wave length (m/s)

                              f = frequency (Hz)

                From the equation (i) ,

                                    frequency (f) = v/λ

                                                           = 4 / 0.22

                                                          = 18.18 /second

frequency (f) of the wave is 18 /sec  or (18 Hz)

Note: frequency is defined as "number of occurrences per unit time", measured in Hz.

Answer 2

Answer:

c) $18s^{-1}$

Explanation:

The information we have is:

Speed: $v=4m/s$

wavelength: $\lambda = 22cm$ we need to convert this quantity to meters:

$22cm=22/100m=0.22m$, so $\lambda =0.22m$

------------------------------------------------

We need to find the frequency of the wave, for that we use the formula:

$v=f\lambda$

where $f$ is the frequency.

In tha last equation we clear for $f$

$f=\frac{v}{\lambda }$

and we substitute the known values:

$f=\frac{4m/s}{0.22m}\\ f=18.18s^{-1}$

the answer is c) $18s^{-1}$