Question 1.
The muscular diaphragm that controls the size of the pupil is
(a) cornea
(b) ciliary muscles
(c) iris
(d) retina
Answer/Explanation
Answer: c
Explanation:
(c) Iris control the size of pupil.
- Having two eyes facilitates in
A : Increasing the field of view
B : Bringing three-dimensional view
C : Developing the concept of distance/ size
Then the correct option is/are
(a) A only
(b) A and B only
(c) B only
(d) A, B and C
Answer: (d)
- The black opening between the aqueous humour and the lens is called
(a) retina
(b) iris
(c) cornea
(d) pupil
Answer/Explanation
Answer: d
Explanation:
(d) The black opening between the aqueous humour and the eye lens is called pupil.
- Near and far points of a young person normal eye respectively are
(a) 0 and infinity
(b) 0 and 25 cm
(c) 25 cm and infinity
(d) 25 cm and 150 cm.
Answer/Explanation
Answer: c
Explanation:
(c) Near point = 25 cm while far point = infinity.
- The defect of vision in which the person is able to see distant object distinctly but cannot see nearby objects clearly is called
(a) Long-sightedness
(b) Far-sightedness
(c) Hypermetropia
(d) All above
Answer/Explanation
Answer: d
Explanation:
(d) Hypermetropia is also called long-sightedness or far-sightedness.
6. The ability of eye lens to adjust its focal length to form a sharp image of the object at varying distances on the retina is called
(a) Power of observation of the eye
(b) Power of adjustment of the eye
(c) Power of accommodation of the eye
(d) Power of enabling of the eye
Answer/Explanation
Answer: c
Explanation:
(c) It is called power of accommodation of the eye.
- Myopia and hypermetropia can be corrected by
(a) Concave and plano-convex lens
(b) Concave and convex lens
(c) Convex and concave lens
(d) Plano-concave lens for both defects.
Answer/Explanation
Answer: b
Explanation:
(b) Myopia is corrected by using of suitable power of concave lens while hypermetropia is corrected by convex lens.
- Bi-focal lens are required to correct
(a) astigmatism
(b) coma
(c) myopia
(d) presbyopia
Answer/Explanation
Answer: d
Explanation:
(d) Bifocal lens are required to correct the presbyopia. Upper point of bifocal lens consists of concave lens used for distant vision while lower point consists of convex lens facilitate near vision.
9. The defective eye of a person has near point 0.5 m and point 3 m. The power far corrective lens required for
(i) reading purpose and
(ii) seeing distant objects, respectively are:
(a) 0.5 D and +3D
(b) +2D and – (\frac{1}{3}) D
(c) – 2D and + (\frac{1}{3})D
(d) 0.5 D and-3.0 D
Answer/Explanation
Answer: b
Explanation:
(b) For reading purpose
- The image formed on the retina of the human eye is
(a) virtual and inverted
(b) real and inverted
(c) real and erect
(d) virtual and erect
Answer/Explanation
Answer: b
Explanation:
(b) Eye lens is convex in nature. So, image formed by it on the retina is real and inverted.
- When white light enters a prism, it gets split into its constituent colours. This is due to
(a) different refractive index for different wavelength of each colour
(b) each colours has same velocity in the prism.
(c) prism material have high density.
(d) Scattering of light
Answer/Explanation
Answer: a
Explanation:
(a) Dispersion takes place because refractive index of the material of prism is different for different wavelength.
12.
The air layer of atmosphere whose temperature is less then the hot layer behave as optically
(a) denser medium
(b) rarer medium
(c) inactive medium
(d) either denser or rarer medium
Answer/Explanation
Answer: a
Explanation:
(a) The cold air layer of the atmosphere acts as a optically denser medium than hot air because the molecules are closely packed together.
- Refraction of light by the earth’s atmosphere due to variation in air density is called
(a) atmospheric reflection
(b) atmospheric dispersion
(c) atmospheric scattering
(d) atmospheric refraction
Answer/Explanation
Answer: d
Explanation:
(d) This phenomena is called atmospheric refraction.
- The deflection of light by minute particles and molecules of the atmosphere in all direction is called __ of light.
(a) dispersion
(b) scattering
(c) interference
(d) tyndell effect
Answer/Explanation
Answer: b
Explanation:
(b) The said phenomenon is called scattering of light.
- One cannot see through the fog, because
(a) refractive index of the fog is very high
(b) light suffers total reflection at droplets
(c) fog absorbs light
(d) light is scattered by the droplets
Answer/Explanation
Answer: d
Explanation:
(d) Objects are not visible through the fog because droplets scatter the light rays.
Important Link
Quick Revision Notes : Human Eye and Colourful World
NCERT Solution : Human Eye and Colourful World
IMPORTANT QUESTION : Human Eye and Colourful World
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