Question

White light is incident from under water on the water-air interface. If the angle of incidence is slowly increased from zero, the emergent beam coming out into the air will turn from

• A. white to violet
• B. white to red
• C. white to black
• D. None of the above

Answer 1

The correct option is A white to violet

For $\sin {\theta }_c=\frac{1}{\mu }$

$Q_c={\sin }^{-1}\left(\frac{1}{\mu }\right)$

So, White to violet

$F_{old}=\frac{k\left(5\times 2\right)}{r^2}=\frac{1}{4\pi {\epsilon }_0}\frac{5\times 2}{r^2}$