What is reflection of light? Write law of reflection and draw labelled diagram.

Image formed by a plane mirror is erect, virtual and _____.

When any empty test-tube is submerged inclinely in a water filled beaker, its surface appears silvery shining. Why? Explain with diagram.

The position of fish in a pond is not same as it is observed from outside. Why? Explain with diagram.

If the object is at a distance of $3 \mathrm{cm}$ from the plane mirror, then the distance of the image will be:

Write any three uses of plane mirror.

Light enters from air to glass plate having $1.50$ refractive index. What is the speed of light in glass? (Given-speed of light in vacuum $3\times {10}^8 \mathrm{m} {\mathrm{s}}^{-1}$)

A fish seems to be at the depth of $75 \mathrm{cm}$ from the surface of a pond, then find out its actual depth from the surface. (Given-refractive index of water $\frac{4}{3}$)