Question

Calculate the energy of a photon of wavelength 6600 angstroms.

(a) 30 × 10^-19 J

(b) 3 × 10^-19 J

(c) 300 × 10^-19 J

(d) 3000 × 10^-19 J

The question was posed to me in an interview for internship.

The above asked question is from Photoelectric Effect in section Dual Nature of Radiation and Matter of Physics – Class 12

Answer 1

Right choice is (b) 3 × 10^-19 J

For explanation: Given: λ = 6600 angstrom = 6600 × 10^-10 m.

Energy of a photon = \(\frac {hc}{\lambda }\)

E = \(\frac {(6.6 \times 10^{-34} \times 3 \times 10^8)}{(6600 \times 10^{-10})}\)

E = 3 × 10^-19 J