Radiation of intensity 1 W/m² are striking on a metal plate. The pressure on the plate is:

0.66 × 10^-8 N/m²

As metal is reflecting surfaces and for reflecting surface radiation pressure,

$\mathrm{p}_{\mathrm{r}}=\frac{2 \mathrm{~S}}{\mathrm{c}}=\frac{2 \times 1}{3 \times 10^8}=0.667 \times 10^{-8} \mathrm{~N} / \mathrm{m}^{-2}$