Question

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

Answer: (A)

$E_{ph}=\frac{1240}{\lambda \left(\right. \text{in} nm \left.\right)}eV=\frac{1240}{450}\times 1.6\times \left(10\right)^{- 19}=4.41\times \left(10\right)^{- 19}J$