Question

What is the frequency of radiation whose wavelength is 2.51 x 10 -7m?​

Answer 1

The frequency of radiation : 1.2 x 10¹⁵ Hz

Further explanation

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

$\large{\boxed{\bold{E\:=\:h\:.\:f}}}$

Where

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

f = Frequency of electromagnetic waves

f = c / λ

c = speed of light

= 3.10⁸  m/s

λ = wavelength

Wavelength-λ is 2.51 x 10⁻⁷m

The frequency :

$\tt f=\dfrac{3.10^8}{2.51\times 10^{-7}}=1.2\times 10^{15}$