What will be the expression for the energy of a photon of wavelength (\( \lambda \))?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \( (h c)\,\lambda^{-1} \)
The energy of a photon is \( E = h\nu \), and the frequency and wavelength are linked by \( c = \nu\lambda \).
\( \displaystyle E = h\nu = \frac{hc}{\lambda} = (hc)\,\lambda^{-1} \)
Note: A similar question was also asked in CUET (UG) 2025 on 22-05-2025 (Slot 1).
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 – “… (iii) All photons of light of a particular frequency ν, or wavelength λ, have the same energy E (=hν = hc/λ) and momentum p (= hν/c = h/λ), whatever the intensity of radiation may be.”