One of the necessary conditions for total internal reflection to take place is ($i =$ angle of incidence,$i_{c} =$ critical angle).

The critical angle of light going from medium $x$ to medium $y$ is $\theta$. The speed of light in medium $x$ is $v$. The speed of light in medium $y$ is:

In an optical fibre,the core and cladding are made with materials of refractive indices $1.5$ and $1.414$ respectively. To observe total internal reflection,what will be the range of the incident angle with the axis of the optical fibre?

$A$ diver at a depth of $12 \ m$ in water $\left(\mu = \frac{4}{3}\right)$ sees the sky in a cone of semi-vertical angle:

$A$ cut diamond sparkles because of its

If the critical angle for total internal reflection from a medium to vacuum is $30^o$,the velocity of light in the medium is