Question

The amplitude of the electric field in a parallel beam of light of intensity $2.0W{m}^{-2}$ is:

• A. $19.4$ N/C
• B. $38.8$ N/C
• C. $4.85$ N/C
• D. $77.9$ N/C

Answer 1

The correct option is B $38.8$ N/C

we know that,

$E_0=\sqrt{\frac{2I}{{ϵ}_{0}C}}$

It is given that $I=2w/m^2.$so,

$E_0=\sqrt{\frac{2\times 2}{(8.85\times {10}^{-12}\times 3\times {10}^8)}}=38.8N/C$

Option -B is correct.