The amplitude of electric field in a parallel beam of light of intensity 4 Wm−2 is
Answer & explanation
Correct answer: option 4
$I=\frac{1}{2}ε_0E^2_0 c$
$or \, E_2 = \sqrt{\frac{2I}{ε_0c}}$
$=\sqrt{\frac{2×4}{(8.85×10^{-12})×(3×10^8)}}$
$ = 55.5 \, NC^{-1}$