Answer
The amplitude of the electric field component is $~~1.9~V/m$
Work Step by Step
If unpolarized light is transmitted through a polarizing sheet, then the transmitted intensity is half of the initial intensity.
The transmitted intensity is $I = 5.0~mW/m^2$
We can find the amplitude of the electric field component:
$\frac{E^2}{2c\mu_0} = I$
$E^2 = 2c~\mu_0~I$
$E = \sqrt{2c~\mu_0~I}$
$E = \sqrt{(2)(3.0\times 10^8~m/s)~(4\pi\times 10^{-7}~H/m)~(5.0\times 10^{-3}~W/m^2)}$
$E = 1.9~V/m$
The amplitude of the electric field component is $~~1.9~V/m$
