Objective question

1. Light And Human Eye
1.Which of the following is the mirror formula?
[A] v + u =f
[B] 1/v + 1/u = 1/f
[C] 1/v + 1/u = f
[D] None of the above
2.What do we call the phenomenon of light being deflected when travelling
obliquely from one medium to another?
[A] Refraction
[B] Reflection
[C] Dispersion
[D] Convergence
3.Which of the following represents the Snell’s law?
[A] sine of angle of incidence/sine of angle of refraction = constant
[B] cosine of angle of incidence/cosine of angle of refraction = constant
[C] tangent of angle of incidence/tangent of angle of refraction = constant
[D] angle of incidence – angle of refraction = constant

2. Light And Human Eye
4.What is the refractive index of water?
[A] 1
[B] 1.01
[C] 1.33
[D] 1.78
5.What happens when light travels from a denser medium to a rarer medium?
[A] it slows down and bends towards the normal
[B] it speeds up and bends towards the normal
[C] it slows down and bends away from the normal
[D] it speeds up and bends away from the normal
6.Where will be the image formed by a convex lens when the object is placed at
the focus?
[A] No image is formed
[B] At focus
[C] Between focus and optical centre
[D] At infinity

3. Light And Human Eye
7.Which of the following gives the power of a lens?
[A] equal to its focal length
[B] reciprocal of its focal length
[C] half of its focal length
[D] double the focal length
8.Which of the following is true about a concave lens?
[A] power of a concave lens is positive
[B] power of a concave lens is negative
[C] power of a concave lens is zero
[D] None of the above
9.What is the S.I. unit of power of a lens?
[A] metre
[B] watt
[C] dioptre
[D] second

4. Light And Human Eye
10.Which of the following is true about the focal length of a spherical mirror?
[A] it is equal to its radius of curvature
[B] it is equal to half its radius of curvature
[C] it is equal to twice its radius of curvature
[D] None of the above
11.What do we call the ratio of the speed of light in vacuum to speed of light in a
medium?
[A] power of that medium
[B] refractive index of that medium
[C] reflective index of that medium
[D] None
12.What is the eye defect when a person can see nearby objects clearly but cannot
see distant objects distinctly known as?
[A] Cataract
[B] Myopia
[C] Hypermetropia
[D] Presbyopia

5. Light And Human Eye
13.Which of these phenomenon is due to the scattering of light?
[A] blue colour of sky
[B] reddening of the Sun at sunrise
[C] reddening of the Sun at sunset
[D] All of the above
14.What causes the twinkling of stars?
[A] Atmospheric refraction of starlight
[B] Dispersion of starlight
[C] Scattering of starlight
[D] None
15.Which of the following eye-defects is also known as far -sightedness?
[A] Myopia
[B] Hyper-metropia
[C] Cataract
[D] None

6. Light And Human Eye
16.What do we call the long-sightedness caused by loss of elasticity of the lens of
the eye?
[A] Myopia
[B] Presbyopia
[C] Hypermetropia
[D] None
17.Which of the following regions of electromagnetic spectrum is called as light?
[A] 100 nm – 1000 nm
[B] 400 nm – 10000 nm
[C] 100 nm – 20000 nm
[D] 400 nm – 750 nm
18.What is the distance between the focus and the pole of the mirror is known as?
[A] Centre of Curvature
[B] Focal length
[C] Mirror number
[D] Radius of curvature

7. Light And Human Eye
19.Which of the following is a law of reflection?
[A] angle of incidence is equal to the angle of reflection
[B] angle of incidence is equal to twice the angle of reflection
[C] angle of incidence is equal to half of the angle of reflection
[D] angle of incidence is always complimentary to the angle of reflection
20.What of the following represents linear magnification?
[A] ratio of the height of the image to the height of the object
[B] ratio of the height of the object to the height of the image
[C] product of the height of the object to the height of the image
[D] difference of the height of the image to the height of the object
21.What is the phenomenon of bouncing back of light in the same medium on
striking the surface of any object known as?
[A] Refraction
[B] Absorption
[C] Reflection
[D] Diffusion

8. Light And Human Eye
22.What is the size of the image formed by a concave mirror when the object is at
focus?
[A] Enlarged
[B] Point sized
[C] Same size
[D] Highly enlarged
23.What is the splitting of light into its colours known as?
[A] Diffusion
[B] Dispersion
[C] Refraction
[D] None of the above
24.What part of eyes give it a distinctive colour?
[A] Cornea
[B] Iris
[C] Pupil
[D] Retina

9. Light And Human Eye
25.Which of the following part of eyes controls the size of the pupil?
[A] Retina
[B] iris
[C] Cornea
[D] None of the above
26.For how long approximately an image persists on the retina before vanishing?
[A] 1/8 seconds
[B] 1/16 seconds
[C] 1/32 seconds
[D] 1 second
27.In which of the following cases a concave mirror will form a virtual and erect
image?
[A] when object is placed at infinity
[B] when object is at focus
[C] when object is between pole and focus
[D] None of the above

10. Light And Human Eye
28.Which of the following are the cases of use of concave mirrors?
[A] Search-lights
[B] Shaving mirrors
[C] Solar furnaces
[D] All of the above
29.What is the nature of image formed by a convex mirror when the object is
placed at infinity?
[A] Real and inverted
[B] Virtual and erect
[C] Virtual and inverted
[D] Real and erect
30.Which of the following mirrors is commonly used as rear-view mirror in a
vehicle?
[A] Concave mirror
[B] Convex mirror
[C] Plain mirror
[D] None of the above