An angular magnification (magnifying power) of \(30\mathrm{X}\) is desired using an objective of focal length \(1.25~\text{cm}\) and an eyepiece of focal length \(5~\text{cm}\). The separation between the objective lens and the eyepiece should be:
1. \(11.67~\text{cm}\)
2. \(10.23~\text{cm}\)
3. \(12.21~\text{cm}\)
4. \(13.13~\text{cm}\)

Digital movie projectors work on the principle of:

(1) Reflection from micromirrors

(2) Refraction from thin lenses

(3) Dispersion from thin prisms

(4) Total internal reflection from optical fibres

Day and night settings for rearview mirrors use:

(1) Thin mirrors

(2) Thick wedge-shaped mirrors

(3) Convex mirrors

(4) Concave mirrors

When a beam of light is incident on a plane mirror, it is found that a real image is formed. The incident beam must be:

(1) Converging

(2) Diverging

(3) Parallel

(4) Formation of the real image by a plane mirror is impossible

An object is placed symmetrically between two plane mirrors inclined at an angle of 72^o, then the total number of images observed is:

(1) 5

(2) 4

(3) 2

(4) Infinite

A person 1.6 m tall is standing at the centre between two walls three metres high. What should be the minimum size of a plane mirror fixed on the wall in front of him if he is to see the full height of the wall behind him?

(1) 0.8 m

(2) 1 m

(3) 1.5 m

(4) 2.3 m

While capturing solar energy for commercial purposes, we use:

(1) Parabolic mirrors

(2) Plane mirrors

(3) Convex mirrors

(4) Concave mirrors

A concave mirror of focal length \(f\) produces an image \(n\) times the size of the object. If the image is real, then the distance of the object from the mirror is:
1. \((n-1)f\)
2. \(\frac{(n-1)}{n}f\)
3. \(\frac{(n+1)}{n}f\)
4. \((n+1)f\)

An object placed in front of a concave mirror of focal length 0.15 m produces a virtual image that is twice the size of the object. The position of the object with respect to the mirror is:

(1) -5.5 cm

(2) -6.5 cm

(3) -7.5 cm

(4) -8.5 cm

When a light ray from a rarer medium is refracted into a denser medium, its:

(1) Speed increases, wavelength increases

(2) Speed decreases, wavelength increases

(3) Speed increases, wavelength decreases

(4) Speed decreases, wavelength decreases