The energy of a photon of wavelength 1 Å is

(Given: $h = 6.63 × 10^{-34} Js$)

$1.24 × 10^4 eV$

The correct answer is Option (1) → $1.24 × 10^4 eV$

Energy of photon: $E = \frac{hc}{\lambda}$

Given: $h = 6.63 \times 10^{-34} \ \text{J·s}$, $c = 3 \times 10^8 \ \text{m/s}$, $\lambda = 1 \ \text{Å} = 1 \times 10^{-10} \ \text{m}$

$E = \frac{6.63 \times 10^{-34} \times 3 \times 10^8}{1 \times 10^{-10}}$

$E = \frac{19.89 \times 10^{-26}}{10^{-10}}$

$E = 1.989 \times 10^{-15} \ \text{J}$

∴ Energy of photon $= 1.99 \times 10^{-15} \ \text{J} = 1.24 × 10^4 eV$