Question

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

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

Answer 1

Answer: (D)

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