Question

The energy of a photon of light of wavelength 450 nm is

• A. $4.4\times {10}^{-19}J$
• B. $2.5\times {10}^{-19}J$
• C. $1.25\times {10}^{-17}J$
• D. $2.5\times {10}^{-17}J$

Answer 1

The correct option is A

$4.4\times {10}^{-19}J$

$E=\frac{hc}{\lambda }=\frac{6.62\times {10}^{-34}\times 3\times {10}^8}{450\times {10}^{-9}}=4.4\times {10}^{-19}J$