The wavelength of light : 4.14 x 10⁻⁵ m
Radiation energy is absorbed by photons
The energy in one photon can be formulated as
[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]
Where
h = Planck's constant (6,626.10⁻³⁴ Js)
f = Frequency of electromagnetic waves
The energy of the light = 4.8 x 10⁻²¹ J
The wavelength of light :
[tex]\tt E=h.\dfrac{c}{\lambda}\\\\\lambda=\dfrac{h.c}{E}\\\\\lambda=\dfrac{6.626.10^{-34}\times 3.10^8}{4.8.10^{-21}}\\\\\lambda=4.14.10^{-5}~m[/tex]