Question

Visible light has wavelengths in the range of 400 nm to 780nm to 780nm. calculate the range of energy of the photons of visible light .

Answer 1

The forces acts on mass length

The forces acts on the thread

${\lambda }_1=400$nm

${\lambda }_2=780$nm

$E=h\lambda =\frac{hc}{\lambda }$

$h=6.63\times {10}^{-34}$J.se

$c=3\times {10}^8$

$E_1=\frac{6.63\times {10}^{-34}\times 3\times {10}^8}{400\times {10}^{-9}}=\frac{6.63\times 3}{4}\times {10}^{-19}=5\times {10}^{-19}J$

$E_2=\frac{6.63\times 3}{7.8}\times {10}^{-19}=2.55\times {10}^{-19}J$

Range $5\times {10}^{-19}J$ to $2.55\times {10}^{-19}J$.