Which type of reflection will be represented by light reflected from a book?

What is the distance between the pole and the principal focus of a spherical mirror called?

Where should an object be placed to use a convex lens as a simple microscope?

$A$ convex mirror has a focal length $f$. $A$ real object is placed at a distance $f$ in front of it. The mirror produces an image at

The following table gives the values of refractive indices of a few media:

$S.No.$	$1$	$2$	$3$	$4$	$5$
Medium	Water	Crown glass	Rock salt	Ruby	Diamond
Refractive index	$1.33$	$1.52$	$1.54$	$1.71$	$2.42$

Use this table to give an example of $(i)$ a medium pair so that light speeds up when it goes from one of these media to another. $(ii)$ a medium pair so that light slows down when it goes from one of these media to another.

When an object is placed between the principal focus $(F)$ and the pole $(P)$ of a concave mirror,what kind of image is formed?