Question

A light wave is incident normally on a glass slab of refractive index $1.5$. If $4\%$ of light gets reflected and the amplitude of the electric field of the incident light is $30V/m$,then the amplitude of the electric field for the wave propogating in the glass medium will be:

• A. $10V/m$
• B. $24V/m$
• C. $30V/m$
• D. $6V/m$

Answer 1

The correct option is B $24V/m$

$P_{refracted}=\frac{96}{100}{P}_1$

$\Rightarrow K_2{A}_t^2=\frac{96}{100}{K}_1{A}_i^2$

$\Rightarrow r_2{A}_t^2=\frac{96}{100}{r}_1{A}_i^2$

$\Rightarrow A_t^2=$ $\frac{96}{100}\times$ $\frac{1}{3}2\times (30{)}^2$

$A_t=\sqrt{\frac{64}{100}\times (30{)}^2}=24$