$A$ well-cut diamond appears bright because

$A$ ray of light travels from an optically denser medium to a rarer medium. The critical angle for the two media is $C$. The maximum possible deviation of the refracted light ray can be:

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

Total internal reflection is possible when light rays travel:

The refractive index of glass is $1.5$ and that of water is $1.33$. The critical angle for a ray of light going from glass to water is

As shown,a narrow beam of light is incident onto a semi-circular glass cylinder of radius $R.$ Light can exit the cylinder when the beam is at the centre. When the beam is moved parallel to a distance $d$ from the central line,no light can exit the cylinder from its lower surface. Find the refractive index of the glass.