Questions
A spherical lens has a minimum of one curved surface. Which of the following spherical lens has two curved surfaces bulging in wards?
- Biconcave
- Planoconcave
- Plano convex
- Biconvex
- Convex
The point where the parallel rays of light converge or diverge after passing through the lens is called the _______________.
- focus
- center of curvature
- pole
- focal length
- radius of curvature
Mohit got a convex lens and coloured it half black. What is the type of image formed?
- Half image
- Clear full image
- Full image with less intensity
- Half clear half dull
- No image
Which of the following statements is / are false regarding the convex lens?
(a) Converging lens
(b) Edges thick and thinner in the middle
(c) Made up of two curved surface
(d) Distance between center of curvature and optical center is the focal length
- only a
- only b
- both a and c
- both b and d
- b, c, and d
Power of lens is in dioptre, and is equal to reciprocal of if its focal length, which is measured in ___________.
- meter
- millimeter
- centimeter
- decimeter
- does not depend on the unit of focal length
In which of the following cases does the ray diagram for concave and convex lens is/are similar?
- When ray of light comes through infinity parallel to principal axis passes through focus.
- When ray of light passing through focus goes parallel to principal axis.
- When ray of light passes through the optical center goes without any deviation.
- All of these
- None of these
Virtual and erect image is formed in a convex lens, when the object is ______________.
- at focus(F1)
- beyond 2F1
- at 2F1
- between F1 and 2F1
- between F1 and O
Which of the following parameters is not used in lens formula?
- Distance of object
- Distance of image
- Focal length of lens
- Height of image
- None of these
Which of the following is correct regarding the blind spot?
- It is the point just after the near point.
- It is the point just after the far point.
- It is the point at which the optic nerve leaves the eyes.
- The dark spots in cornea, found in a blind man.
- The point in the eye, from where there is no vision.
When can a convex lens act as a diverging lens?
- When two convex lens are placed side by side.
- When lens is in a liquid whose refractive index is greater than refractive index of material of lens.
- When a convex lens is placed behind a concave lens.
- When lens is in vacuum.
- When lens is in a liquid whose refractive index is less than refractive index of material of lens.
A person suffering from nearsightedness shrinks his eyes to see the television clearly. What ability of eye is this?
- Power of seeing far things
- Power of accommodation
- Power of muscles
- Power of eye lid
- Power of light adjustment
An old person cannot read and write properly, due to ageing. He is suffering from___________.
- astigmatism
- presbyopia
- myopia
- hypermetropia
- blind spots
________controls the amount of light that can enter the eye.
- Pupil
- Eye lid
- Iris
- Ciliary muscles
- Retina
Match the following lens and disease for which they are use
| 1 | convex lens | a | astigmatism |
| 2 | concave lens | b | hypermetropia |
| 3 | cylindrical lens | c | myopia |
- 1 - c, 2 - a, 3 - b
- 1 - b, 2 - c, 3 - a
- 1 - a, 2 - b, 3 - c
- 1 - b, 2 - a, 3 - c
- 1 - a, 2 - c, 3 - b
Which of the following colours cannot be distinguished by a person suffering from colour blindness?
- Red and green
- Red and yellow
- Any colour
- Blue and white colour
- Black and white colour