Question

The wavelength of the green light from a traffic signal is centred at 522 nm. What is the frequency, v, in Hz, of this radiation?

Answer 1

The frequency is 5.74 × 10⁻¹⁴ Hz

The wavelength λ is the distance between successive peaks in a wave.

The frequency `f` of a wave is the number of complete waves that pass a point in a given time.

The formula relating the frequency `f` and wavelength λ is

`fλ = c` or `f = c/λ`

where `c` is the speed of light.

In your case, `λ` = 522 nm = 522 × 10⁻⁹ m and `c` = 2.998 × 10⁸ m·s⁻¹.

∴ `f = c/λ = (2.998 × 10⁸ cancel("m")"·s⁻¹")/(522 × 10⁻⁹ cancel("m")) = "5.74 × 10¹⁴ s⁻¹"`