Question

What will be the photon energy for a wavelength of 5000 angstroms, if the energy of a photon corresponding to a wavelength of 7000 angstroms is 4.23 × 10^-19 J?

(a) 0.456 eV

(b) 5.879 eV

(c) 3.701 eV

(d) 1.6 × 10^-19 eV

This question was addressed to me during an interview.

This interesting question is from Particle Nature of Light : The Photon topic in chapter Dual Nature of Radiation and Matter of Physics – Class 12

Answer 1

Right answer is (c) 3.701 eV

For explanation: \(\frac {E_2}{E_1} = \frac {\lambda_1}{\lambda_2}\)

\(\frac {\lambda_1}{\lambda_2} = \frac {1.4 \times 4.23 \times 10^{-19}}{1.6 \times 10^{-19}}\) eV

\(\frac {\lambda_1}{\lambda_2}\) = 3.701 eV