A point object O is placed on the principal axis of a convex lens of focal length f = 20 cm at a distance of 40 cm to the left of it. The diameter of the lens is 10 cm. An eye is placed 60 cm to right of the lens and a distance h below the principal axis. The maximum value of h to see the image is

1. 0

2. 2.5 cm

3. 5 cm

4. 10 cm

The rays of different colours fail to converge at a point after going through a converging lens. This defect is called:
1. spherical aberration
2. distortion
3. coma
4. chromatic aberration

If the light moving in a straight line bends by a small but fixed angle, it may be a case of
(a) reflection
(b) refraction
(c) diffraction
(d) dispersion
Choose the correct option:

Mark the correct options:

Which of the following (referred to a spherical mirror) do (does) not depend on whether the rays are paraxial or not?
(a) pole
(b) focus
(c) radius of curvature
(d) principal axis
Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (a), (b) and (c)
4. (a), (c) and (d)

The image of an extended object, placed perpendicular to the principal axis of a mirror, will be erect if

(a) the object and the image are both real

(b) the object and the image are both virtual

(c) the object is real but the image is virtual

(d) the object is virtual but the image is real

Choose the correct option:

1. (a) and (b)

2. (b) and (c)

3. (c) and (d)

4. (a) and (d)

A convex lens forms a real image of a point object placed on its principal axis. If the upper half of the lens is painted black,

Choose the correct option:

Consider three converging lenses \(L_1,\) \(L_2\) and \(L_3\) having identical geometrical construction. The index of refraction of \(L_1\) and \(L_2\) are \(\mu\)₁ and \(\mu\)₂ respectively. The upper half of the lens \(L_3\) has a refractive index \(\mu\)₁ and the lowest half has \(\mu\)₂ (figure). A point object \(O\) is imaged at \(O_1\) by the lens \(L_1\) and at \(O_2\) by the lens \(L_2\) placed in same position. If \(L_3\) is placed at the same place,

Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (c) and (d)
4. all of these

A screen is placed a distance 40 cm away from an illuminated object. A converging lens is placed between the source and the screen and it is attempted to form the image of the source on the screen. If no position could be found, the focal length of the lens

1. must be less than 10 cm

2. must be greater than 20 cm

3. must not be greater than 20 cm

4. must not be less than 10 cm

The size of an object as perceived by an eye depends primarily on

1. actual size of the object

2. distance of the object from the eye

3. aperture of the pupil

4. size of the image formed on the retina