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

Where should an object be placed in front of a convex lens to get a real image of the size of the object?

We wish to obtain an erect image of an object,using a concave mirror of focal length $15\, cm$. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.

You are given kerosene,turpentine,and water. In which of these does the light travel fastest? Use the information given in the table below.

Material medium	Refractive index
Water	$1.33$
Kerosene	$1.44$
Turpentine oil	$1.47$

Name the mirror that can give an erect and enlarged image of an object.

An object $5.0\, cm$ in length is placed at a distance of $20\, cm$ in front of a convex mirror of radius of curvature $30\, cm$. Find the position of the image,its nature and size.