Write Snell's law of refraction of light. OR Write two characteristics of the image of an extended object formed when it is placed in between the optical centre and focus of a thin convex lens.

Define dispersion of light. How would you identify monochromatic light and composite light with the help of a prism? [1 + 2]

Write down the relationship between relative refractive index and absolute refractive index. On which factors does the relative refractive index of a medium depend? [1 + 2] OR Show that if a monochromatic light ray passes symmetrically through an equilateral prism then the angle of deviation of that ray will be minimum

Where is the image formed if the object is placed in between f and 2f of a convex lens ?

State whether the refractive index of a medium would increase or decrease if the angle of incidence is increased.

A ray parallel to the principal axis of a concave mirror follows which path after reflection by the concave mirror?

Write one use of a convex mirror

In the case of refraction of white light through a prism, the light of colour which deviates the least is yellow orange red violet

What is meant by the principal axis of a concave lens?

Determine the angle of deviation for the refraction of light rays from rarer to denser medium. [2] (angle of incidence = i, angle of refraction = r) OR Why do the green leaves of trees appear 'green' in sunlight? [2]

At what angle must a light ray fall on the surface of an equilateral prism so that its angle of minimum deviation will be 20°? OR Calculate the time required by a ray of light to traverse a glass slab of thickness 2 mm. The refractive index of glass=1.5.

Explain with a diagram why the sky appears blue.