Question

Energy of a photon of light with wavelength $4.00 \times 10^{3} nm$ is $y \times 10^{-20}$ Joules. The value of $y$ is______.
[Given: $h =6.626 \times 10^{-34} J\, s , c =3 \times 10^{8} ms ^{-1}$ ]

Answer 1

$E =\frac{ hc }{\lambda}=\frac{6.626 \times 10^{-34} J s \times 3 \times 10^{8} m s ^{-1}}{4.00 \times 10^{3} \times 10^{-9} m }$
$=4.97 \times 10^{-20} J$
$\therefore $ Value of $y =4.97$