Which of the following pairs are correctly matched?
$\mathrm{I}$. Power of lens: diopter
$\mathrm{II}$. Two waves of same frequency: diffraction and amplitude having constant phase difference
$\mathrm{III}$. Total internal reflection: optical fibre
$\mathrm{IV}$. Change of focal length of a lens with colour: spherical aberration

Consider the following statement(s):

$\mathrm{I}$. Compound microscope has an objective lens with a very short focal length.
$\mathrm{II}$. Simple microscope is of a strong converging lens system.
$\mathrm{III}$. Television camera converts the optical image into electrical video signals.
$\mathrm{IV}$. Hypermetropia is corrected by using a diverging lens.

Which of the statement(s) given above is/are correct?

Consider the following statement(s):

$\mathrm{I}$. The focal length of the objective of a microscope is less than the focal length of the eyepiece.
$\mathrm{II}$. The minimum distance between an object and its real image formed by a convex lens of focal length $f$ is equal to $4f$.

Which of the statement(s) given above is/are correct?

Statement $\mathrm{I}$: Convex mirror is used as a driver mirror.
Statement $\mathrm{II}$: Images formed by a convex mirror are diminished in size.

To obtain the powerful parallel beams of light from a vehicle's headlight, one must use,

A refracting telescope consists of