Question

The energy of a photon is $3\times {10}^{-12}$ ergs. What is its wavelength in $nm$ ?
$[h=6.62\times {10}^{-27}erg,c=3\times {10}^{10}cm/s]$

• A. $0.066$
• B. $1324$
• C. $5.62$
• D. $6.62$

Answer 1

Answer: (A)

$0.066$

Given,

$E=3\times {10}^{-12}erg$

$h=6.62\times {10}^{-27}erg$

$c=3\times {10}^{10}cm/s$

The energy of photon is given by

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

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

$\lambda =\frac{6.62\times {10}^{-27}\times 3\times {10}^{10}}{3\times {10}^{-12}}$

$\lambda =6.63\times {10}^{-5}cm$

$\lambda =0.066\times {10}^{-9}m$

$\lambda =0.066nm$

The correct option is A.