Question

Calculate the frequency of visible light having a wavelength of 486 nm?

Answer 1

λf = c = 2.998e8 m/s (speed of light in vacuum)

λ = Wavelength in meters

f = frequency in Hz

f = 2.998e8 / 486e-9 = 6.169e14 Hz

Answer 2

Given:

Wavelength of light wave = 486 nm

Speed of wave = $3 * 10^{8}$ m/s

To find: Frequency of the wave

Calculation:

The expression that relates frequency and wavelength is:

v = f * λ

Where v is the speed of wave, f is the frequency and λ is the wavelength of wave.

• Frequency is the number of cycles that a wave complete in one time period.
• Wavelength is distance between two consecutive repetition of cycle of wave.

Here, wave speed is $3 * 10^{8}$ m/s because it is light wave.

So, $f=\frac{3*10^{8} }{486*10^{-9} }$

f = $0.617*10^{15}$ $s^{-1}$

Answer:

Frequency of light wave is $0.617*10^{15}$ $s^{-1}$.