Question

The energy of a photon of wavelength $390nm$ is nearly

• A. 6.6 eV
• B. 3.2 eV
• C. 5.5 eV
• D. 1.2 eV

Answer 1

Answer: (B)

Energy of photon, $E=\frac{hc}{\lambda }$
$E=\frac{6.6\times 10^{-34}\times 3\times 10^8}{390\times 10^{-9}}$
$=5.0\times 10^{-19}J$
$E=\frac{5.0\times 10^{-19}}{1.6\times 10^{-19}}$
$=3.2eV$