Question

Radiation from a mercury lamp source is of energy 2.845 eV. Calculate the wavelength
of the radiation
a) 579.0 nm
b) 355.0 nm c) 404.7nm d) 435.9 nm​

Answer 1

Explanation:

Energy of radiation

E (in ev)=1240/(wavength in nm) (please remember this formula)

wavelengh=1240/2.845

=435.9nm

Answer 2

The wavelength is 435.9 nm. (option d)

Given,

E = 2.845 eV

To Find,

Wavelength (λ)

Solution,

Using the formula,

E = hν = hc/λ

where,

h = Planck's Constant = 4.14 * 10⁻¹⁵ eV.s

c = Speed of light in vaccum = 3 * 10⁸ m/s

2.845 = (4.14 * 10⁻¹⁵ * 3 * 10⁸)/λ

λ = $\frac{12.42}{2.845}$ * 10⁻⁷ m

λ ≈ 435.9 nm

Hence, the wavelength is 435.9 nm.

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