If the wavelength of purple light is 400 x 10^-9 m, what is the frequency? a) 7.5 x 10^14 /s
b) 8 X 10^14 Hz
c) 7.5 x 10^14 m
d) 8 x 10^14 m

The frequency : a) 7.5 x 10¹⁴ /s

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

Where

h = Planck's constant (6,626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves  (/s or Hz)

f = c / λ

c = speed of light

= 3.10⁸  m/s

λ = wavelength

The wavelength(λ) of purple light is 400 x 10⁻⁹ m, so the frequency :

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