Question

A wavelength of light is 2,000 m. What is the frequency?

Answer 1

Answer 150000Hz

Explanation:

Given that:

Wavelength (λ)= 2000m

Frequency F = ?

Speed of light V = 3 x 10^8 m/s ( Recall that the speed of light is constant, with a value of 3 x 10^8 m/s)

So, apply V = F λ

3 x 10^8m/s = F x 2000m

F = (3 x 10^8m/s ➗ 2000m)

F = 150000Hz

Thus, the frequency of the light wave is 150000 Hz

Answer 2

Frequency is 1.5 × 10^5 Hz

Explanation:

• Wavelength of light is given to be 2000 m. It measures the distance between two successive crests or troughs of the wave. Frequency is given by the following equation

f = c/λ, where f is the frequency, c is the speed of light = 3 × 10^8 m/s and λ is the wavelength.

⇒ f = 3 × 10^8/2000

      = 3/2 × 10^8 × 10^-3

      = 1.5 × 10^5 Hz