Answer:
4.125 × 10^-7m
Step-by-step explanation:
The formula for calculating the energy level of electron is expressed as;
∆E = hf
h is the Planck's constant
f is the frequency
f = velocity of light/wavelength
f = c/λ
c is the velocity of light
λ is the wavelength
∆E = hc/λ
Given ∆E = 3.0eV
Since 1eV = 1.6×10^-19Joules
∆E = 3×1.6×10^-19Joules
∆E = 4.8×10^-19Joules
Other given parameters
c = 3×10^8m/s
h = 6.6×10^-34Js
From the formula ∆E = hc/λ
λ = hc/∆E
λ = 6.6×10^-34 × 3×10^8/4.8×10^-19
λ = 19.8×10^{-34+8}/4.8×10^-19
λ = 19.8×10^-26/4.8×10^-19
λ = 19.8/4.8 × 10^{-26-(-19)}
λ = 19.8/4.8 × 10^{-26+19}
λ = 4.125 × 10^-7m
Hence the wavelength of the electromagnetic radiation is 4.125 × 10^-7m