Monochromatic light of frequency \( 6 \times 10^{14}\,\mathrm{Hz} \) is produced by a laser source. The energy of photon of light is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \( 3.98 \times 10^{-19}\,\mathrm{J} \)
By Planck's relation, the energy of one photon depends only on the frequency of the light.
\( \displaystyle E = h\nu \)
\( h = 6.63\times10^{-34}\,\mathrm{J\,s} \)
\( \nu = 6\times10^{14}\,\mathrm{Hz} \)
\( \displaystyle E = 6.63\times10^{-34} \times 6\times10^{14} = 39.78\times10^{-20}\,\mathrm{J} \approx 3.98\times10^{-19}\,\mathrm{J} \)
Note: This question is from NCERT (2026-27). NTA sets numerical questions from NCERT too, so do not ignore NCERT while practising numericals.
NCERT (2026-27):
Particle Nature of Light: The Photon – …
