State the condition of total internal reflectoin to take place at an interface separating two transparent media. Hence derive the expression for the critical angle in terms of speed of light in two media.

State the condition of total internal reflection. Calculate the speed of light in the medium whose critical angle of 45^@ .

Explain the phenomenon of refraction at a plane surface separating two transparent media and show that mu=c//v where letters have their usual meanings.

What is total internal reflection, state the necessary conditions for it ? Find a relation between refractive index and critical angle.

What is total internal reflection of light ? What are the two essential conditions for total internal reflection to take place ?

State two conditions for two light sources to be coherent. Derive an expression for the fringe width in Young.s double slit experiment for interfernce with suitable diagram.

Fig.2.100 shows a convex spherical surface with centre of curature C,separating the two media of refractive indices mu_1 and mu_2 . . Draw a ray diagram showing the formation of imge of a point object O lying on the principal axis.Derive the relationship between the object and image distances in terms of the refractie indices of the wo media and the radius of curvature R of the surface.