What is the power and focal length- of a parallel glass slab?

What is the focal length of sunglass?

What is the power of a glass plate.

Show that for refraction of light through a parallel glass slab, the incident ray and the emergent ray are parallel to each other. Or, With the help of a diagram show how in case of a rectangular glass slab, when light is refracted by the two parallel faces of the slab, deviation between angle of incidence and angle of refractive is zero.

Show that for an object lying under a parallel glass slab, the apparent displacement of its image in the observer's direction does not depend on the position of the object.

What is the time taken by light to travel through a glass slab of thickness ‘d’ and refractive index mu ?

What is the focal length and the power of a plane mirror?

What will be the equivalent focal length for two lenses of focal length f_1 and f_2 in contact ?

When a ray of light is incident perpendicularly on a transparent glass slab, what will be its angle of deviation?