The figure shows a ray incident at an angle $i = \pi /3.$ If the plot drawn shows the variation of $|r - i|$ versus $\frac{\mu_1}{\mu_2} = k,$ ($r =$ angle of refraction) choose the wrong alternative.

$A$ step index fibre has a relative refractive index difference of $0.88\%$. What is the critical angle at the core-cladding interface in degrees?

For total internal reflection to occur, which one of the following is the correct statement? $(i = \text{angle of incidence}, i_{C} = \text{critical angle})$.

$A$ point source $S$ is placed at the bottom of a transparent block of height $h = 10 \ mm$ and refractive index $n_B = 2.72$. It is immersed in a liquid of lower refractive index $n_L$ as shown in the figure. It is found that the light emerging from the block into the liquid forms a circular bright spot of diameter $D = 11.54 \ mm$ on the top surface of the block. The refractive index of the liquid $n_L$ is:

The speed of light in two media $c_1$ and $c_2$ are $1.5 \times 10^8 \ m/s$ and $2 \times 10^8 \ m/s$ respectively. If the light undergoes total internal reflection,the critical angle between the two media is

$A$ beam containing red,green,and blue light is incident on a prism. Their refractive indices are $1.39, 1.44$,and $1.47$ respectively. Then,the prism: