Question

The number of photons of light having wavelength 100 nm which can provide 1 J energy is nearly

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

$E=n\frac{hc}{\lambda }$
$n=\frac{E\lambda }{hc}=\frac{1\times 100\times {10}^{-9}}{6.626\times {10}^{-34}\times 3\times {10}^8}$
$=5\times {10}^{17}$