Question

The wavelength of light is 310. nm; calculate the frequency.

Answer 1

Explanation:

It is given that wavelength of light is 310 nm or $310 \times 10^{-9}$ m. Relation between wavelength, speed of light and frequency is as follows.

                   $\nu = \frac{c}{\lambda}$

where,      $\nu$ = frequency

                     c = speed of light = $3 \times 10^{8}$ m/s

                $\lambda$ = wavelength

Hence, putting the given values into the above formula as follows.

             $\nu = \frac{c}{\lambda}$

            $\nu = \frac{3 \times 10^{8} m/s}{310 \times 10^{-9} m}$

                       = $9.67 \times 10^{14}$ per second

Thus, we can conclude that the frequency of given light is $9.67 \times 10^{14}$ per second.

Answer 2

Frequency = velocity of propagation / wavelength. 

For light, we assume it is moving in a vacuum, so vp is 3e8 m/s. The wavelength of 310nm is 310e-9 meters. Then we plug the numbers in, and we get (3e8 m/s) / (310e-9 m) = 967.742e12 Hz because 1/s is the same as cycles/sec, which is a Hertz.