The frequency of a photon whose energy is 66.3 eV is-

The correct answer is Option (1) → 1.6 x 10¹⁶ Hz

The energy of a photon is given by Planck’s relation \( E = h\nu \). Convert the energy from eV to joules first.

    \( \displaystyle E = 66.3\,\mathrm{eV} = 66.3 \times 1.6\times10^{-19}\,\mathrm{J} \)

    \( \displaystyle \nu = \frac{E}{h} = \frac{66.3 \times 1.6\times10^{-19}\,\mathrm{J}}{6.63\times10^{-34}\,\mathrm{J\,s}} \)

    \( \displaystyle \nu = 10 \times 1.6\times10^{15}\,\mathrm{Hz} = 1.6\times10^{16}\,\mathrm{Hz} \)

Note: A similar question was also asked in CUET (UG) 2025 on 03-06-2025 (Slot 1).