Question

Energy of a photon of lights is 3 ev. Then the wavelength of photon must be

Answer 1

Given :

Energy = 3ev

(ev = electron volt)

$1ev = 1.602 \times {10}^{ - 19}$

3ev = 3 × 1.602×10^-19

= 4.80 × 10^-19.

Formula :

E = hc / lamda

Derivation :

Lamda = hc/E

Lamda = 6.63 × 10 ^-34 × 3×10^-8

4.80 × 10^-19

= 19.8×10^-42 × 10^19

4.8

lamda = 4.1×10^-23.

Wave length of photon is 4.1× 10^-23.