MCQ on Light Class 8
Choose the correct answer.
Question 1.
A push or a pull is called
A) friction
B) pressure
C) force
D) none of these
Answer:
C) force
Question 2.
Which of the following is required to see an object?
A) eyes
B) light
C) A and B
D) air
Answer:
C) A and B
Question 3.
A mirror changes ………………… of light that falls on it.
A) the speed
B) the direction
C) A and B
D) colour
Answer:
B) the direction
Question 4.
The light ray, which strikes any surface, is called
A) the incident ray
B) the reflected ray
C) normal
D) refracted ray
Answer:
A) the incident ray
Question 5.
The ray that comes back from the surface after reflection is known as
A) the incident ray
B) the reflected ray
C) normal
D) refracted ray
Answer:
B) the reflected ray
Question 6.
The normal is perpendicular to the line of
A) the incident ray
B) the reflected ray
C) surface of the mirror
D) refracted ray
Answer:
C) surface of the mirror
Question 7.
The angle between the normal and incident ray is called
A) the angle of incidence (∠i)
B) the angle of reflection (∠r)
C) the angle of the mirror
D) the angle of refracted ray
Answer:
A) the angle of incidence (∠i)
Question 8.
The angle between the normal and reflected ray is called
A) the angle of incidence (∠i)
B) the angle of reflection (∠r)
C) the angle of the mirror
D) the angle of refracted ray
Answer:
B) the angle of reflection (∠r)
Question 9.
The angle of incidence is always …………………. the angle of reflection.
A) equals to
B) greater than
C) less than
D) B or C
Answer:
A) equals to
Question 10.
The first law of reflection
A) (∠i) > (∠r)
B) (∠i) < (∠r)
C) (∠r) = (∠i)
D) (∠i) = (∠r)
Answer:
D) (∠i) = (∠r)
Question 11.
The light reflects through ……………… if the incident ray passed along the normal.
A) the incident ray
B) the reflected ray
C) surface of the mirror
D) normal
Answer:
D) normal
Question 12.
If the angle of the incidence is 55°, the angle of reflection is
A) 55°
B) 35°
C) 90°
D) 0°
Answer:
A) 55°
Question 13.
If the angle of reflection is 90°, the incident ray passed through
A) outside of the plane
B) the normal
C) surface of the mirror
D) refracted ray
Answer:
B) the normal
Question 14.
The incident ray, the normal at the point of incidence and the reflected ray all lie in the ………………
A) same plane
B) same line
C) same angle
D) opposite plane
Answer:
A) same plane
Question 15.
The source of light is …………………
A) the sun
B) candle
C) bulb
D) above all
Answer:
D) above all
Question 16.
Features of the image of an object formed by a plane mirror is
A) erect
B) virtual
C) lateral inversion
D) above all
Answer:
D) above all
Question 17.
If the distance between mirror and an object is 10 cm, then the distance between mirror and image is ………………..
A) 5 cm
B) 15 cm
C) 10 cm
D) 20 cm
Answer:
C) 10 cm
Question 18.
The image formed by a mirror the left of the object appears on the right and the right appears on the left. This is known as
A) lateral inversion
B) opposite inversion
C) vertical inversion
D) none
Answer:
A) lateral inversion
Question 19.
Laws of the reflection is not applicable in
A) regular reflection
B) diffused reflection
C) A and B
D) none
Answer:
D) none
Question 20.
When all the parallel rays reflected from a rough or irregular surface are not parallel, the reflection is known as …………………
A) regular reflection
B) diffused reflection
C) A and B
D) none
Answer:
B) diffused reflection
Question 21.
When all the parallel rays reflected from a mirror is parallel, the reflection is known as ……………….
A) regular reflection
B) diffused reflection
C) A and B
D) none
Answer:
A) regular reflection
Question 22.
Images are formed by ………………
A) regular reflection
B) diffused reflection
C) A and B
D) none
Answer:
A) regular reflection
Question 23.
The given figure shows ………………..
A) regular reflection
B) diffused reflection
C) A and B
D) none
Answer:
A) regular reflection
Question 24.
The objects which shine in the light of other objects are called ……………….. objects.
A) luminous
B) illuminated
C) light source
D) none
Answer:
B) illuminated
Question 25.
Which is not an illuminated object ?
A) moon
B) mirror
C) sun
D) polished stone
Answer:
C) sun
Question 26.
Which is a luminous object?
A) moon
B) mirror
C) sun
D) polished stone
Answer:
C) sun
Question 27.
Which of the following makes use of two plane mirrors?
A) periscope
B) kaleidoscope
C) microscope
D) above all
Answer:
A) periscope
Question 28.
These are used in submarines, tanks and also by soldiers in bunkers to see things outside.
A) periscopes
B) kaleidoscopes
C) microscopes
D) above all
Answer:
A) periscopes
Question 29.
Number of images are formed if the angle between two plane mirrors is 45°.
A) 8
B) 7
C) 6
D) 9
Answer:
B) 7
Question 30.
Number of images are formed if the angle between two plane mirrors is 120°.
A) 0
B) 1
C) 3
D) 2
Answer:
D) 2
Question 31.
Number of images are formed if the angle between two plane mirrors is 180°.
A) infinity
B) 1
C) 3
D) 2
Answer:
B) 1
Question 32.
How much angle between the two plane mirrors can give 9 images ?
A) 30°
B) 40°
C) 36°
D) 18°
Answer:
C) 36°
Question 33.
Guess the angle between the plane mirrors in the given figure.
A) 30
B) 40°
C) 60°
D) 90°
Answer:
D) 90°
Question 34.
Numerous beautiful patterns are seen in ………………. .
A) periscope
B) kaleidoscope
C) microscope
D) above all
Answer:
B) kaleidoscope
Question 35.
The device shown in the figure is ………………… .
A) periscope
B) kaleidoscope
C) microscope
D) above all
Answer:
B) kaleidoscope
Question 36.
A polished or a shiny surface can act as ……………… .
A) a mirror
B) a lens
C) a microscope
D) above all
Answer:
A) a mirror
Question 37.
Sunlight is
A) a white light
B) combination of seven colours
C) A and B
D) black light
Answer:
C) A and B
Question 38.
The shape of eye is
A) circle
B) spherical
C) half spherical
D) cone
Answer:
B) spherical
Question 39.
The outer coat of eye is
A) red
B) black
C) white
D) grey
Answer:
C) white
Question 40.
The transparent first part in our eye
A) retina
B) lens
C) iris
D) cornea
Answer:
D) cornea
Question 41.
The colour of the cornea is
A) red
B) black
C) white
D) no colour
Answer:
D) no colour
Question 42.
Behind the cornea, we find a dark muscular structure called
A) retina
B) lens
C) iris
D) pupil
Answer:
C) iris
Question 43.
The coloured part in the eye is
A) cornea
B) lens
C) iris
D) pupil
Answer:
C) iris
Question 44.
Pupil is located in
A) cornea
B) lens
C) iris
D) retina
Answer:
C) iris
Question 45.
Pupil is
A) a small hole
B) a lens
C) a colour pigment
D) a nerve cell
Answer:
A) a small hole
Question 46.
Pupil is controlled by
A) cornea
B) lens
C) iris
D) retina
Answer:
C) iris
Question 47.
Colour of the pupil is
A) red
B) black
C) white
D) no colour
Answer:
B) black
Question 48.
……………….. controls the amount of light entering into the eye.
A) cornea
B) lens
C) iris
D) retina
Answer:
C) iris
Question 49.
The correct order of parts of an eye is
A) cornea-lens-retina-iris
B) lens-cornea-retina-iris
C) iris-lens-retina
D) cornea-iris-lens-retina
Answer:
D) cornea-iris-lens-retina
Question 50.
In this way pupil responds in a dim light
A) enlarges
B) contracts
C) closes
D) no change
Answer:
A) enlarges
Question 51.
In which case do you need to allow more light in the eye, when the light ………………
A) dim
B) bright
C) A or B
D) never
Answer:
A) dim
Question 52.
The lens focuses light on the back of the eye, on a layer called
A) cornea
B) lens
C) iris
D) retina
Answer:
D) retina
Question 53.
Which is acts as a screen in the eye?
A) cornea
B) lens
C) iris
D) retina
Answer:
D) retina
Question 54.
Which is connected to an optical nerve?
A) cornea
B) lens
C) retina
D) iris
Answer:
C) retina
Question 55.
Which of the following cells are located in the retina?
A) cones
B) rods
C) A and B
D) none
Answer:
C) A and B
Question 56.
Which of the following cells are sensitive to bright light ?
A) cones
B) rods
C) A and B
D) none
Answer:
A) cones
Question 57.
Which of the following cells are sensitive to dim light?
A) cones
B) rods
C) A and B
D) none
Answer:
D) none
Question 58.
Which of the following cells are sensitive to colours ?
A) cones
B) rods
C) A and B
D) none
Answer:
A) cones
Question 59.
What does find at the junction of the optic nerve and the retina ?
A) cones
B) rods
C) A and B
D) none
Answer:
D) none
Question 60.
What does find at the junction of the optic nerve and the retina ?
A) cones
B) rods
C) A and B
D) blind spot
Answer:
D) blind spot
Question 61.
Blind spot contains
A) cones
B) rods
C) A and B
D) no cells
Answer:
D) no cells
Question 62.
No visionary part in the eye is
A) cones
B) rods
C) blind spot
D) above all
Answer:
C) blind spot
Question 63.
Which of the following is the correct statement ?
P) The impression of an image does not vanish immediately from the retina.
Q) It persists there for about 1/16th of a minute.
A) P only
B) Q only
C) both P and Q
D) none
Answer:
A) P only
Question 64.
The impression of an image on the retina vanishes after ………………. a second.
A) 1/9th
B) 1/16th
C) 1/19th
D) one
Answer:
B) 1/16th
Question 65.
If still images of a moving object are flashed on the eye1 at a rate faster than …………… per second, then the eye perceives this object as moving.
A) 1
B) 16
C) 8
D) 0
Answer:
B) 16
Question 66.
Cinema reels are made to move across the eye usually at the rate of …………………. pictures per second.
A) 24
B) 16
C) 9
D) 10
Answer:
A) 24
Question 67.
Which of the following prevents entering of any object into the eye ?
A) cones
B) rods
C) eyelids
D) eye brows
Answer:
C) eyelids
Question 68.
Which of the following object can see by the eye ?
A) nearby
B) far
C) A and B
D) no object
Answer:
C) A and B
Question 69.
The most comfortable distance at which one can read with a normal eye is about ……………… .
A) 25 cm
B) 25 m
C) 2.5 cm
D) 2.5 m
Answer:
A) 25 cm
Question 70.
Eye defects can be corrected by
A) mirrors
B) lenses
C) medicines
D) braille
Answer:
B) lenses
Question 71.
Cataract is
A) short-sightedness
B) long-sightedness
C) cloudy eye lens
D) colour blindness
Answer:
C) cloudy eye lens
Question 72.
Which of the following can see in night?
A) owl
B) eagle
C) kite
D) above all
Answer:
A) owl
Question 73.
Which of the following can see the objects at back side?
A) butterfly
B) crab
C) A and B
D) eagle
Answer:
C) A and B
Question 74.
The owl has
A) large cornea
B) large pupil
C) large number of rods
D) above all
Answer:
D) above all
Question 75.
If particles of dust go into your eyes
A) rub your eyes
B) wash your eyes with clean water
C) go to a doctor
D) B or C
Answer:
D) B or C
Question 76.
Night blindness is caused by the deficiency of
A) Vitamin A
B) Vitamin B complex
C) Vitamin C
D) Vitamin K
Answer:
A) Vitamin A
Question 77.
Vitamin A contains in
A) raw carrots
B) broccoli
C) eggs
D) above all
Answer:
D) above all
Question 78.
Which of the following is not a Non-optical aid ?
A) visual aids
B) tactual aids
C) auditory aids
D) contact lenses
Answer:
D) contact lenses
Question 79.
Which of the following is not an optical aid ?
A) contact lenses
B) tactual aids
C) tinted lenses
D) auditory aids
Answer:
B) tactual aids
Question 80.
Braille system has …………………. dot patterns or characters.
A) 63
B) 36
C) 56
D) 24
Answer:
A) 63
Question 81.
Braille system was developed by
A) Louis Braille
B) Helen A. Keller
C) Ravindra Jain
D) Above all
Answer:
A) Louis Braille
Question 82.
Splitting of light into its colours is known as dispersion
A) reflection
B) dispersion
C) inversion
D) scattering
Answer:
B) dispersion
Question 83.
Find the values of ∠i, ∠r in the diagram.
A) ∠i = 60°, ∠r = 60°
B) ∠i = 60°, ∠r = 30°
C) ∠i = 30°, ∠r1 = 60°
D) ∠i = 30°, ∠r = 30°
Answer:
D) ∠i = 30°, ∠r = 30°
Question 84.
The angle of incidence is the angle between
A) The incident ray and surface of the mirror
B) The reflected ray and surface of the mirror
C) The normal to the surface and incident ray
D) The normal to the ,surface, and reflected ray
Answer:
C) The normal to the surface and incident ray
Question 85.
In the given figure the value of x and y are
A) 40°, 40°
B) 90°, 90°
C) 50°, 50°
D) 180°
Answer:
A) 40°, 40°
Question 86.
For a plane mirror, the incorrect statement is
A) it forms a real image
B) image is as far behind the mirror as far the object is in front of it
C) the image formed is erect
D) the image formed is of the same size as the object
Answer:
A) it forms a real image
Question 87.
The figure given below shows the image of a clock as seen in a plane mirror. The correct time is ……………. .
A) 2 : 25
B) 2 : 35
C) 6 : 45
D) 9 : 25
Answer:
D) 9 : 25
Question 88.
Choose the correct mirror image of
Answer:
A
Question 89.
Select the correct pair of incidence and reflected rays
A) (l, o) and (m, n)
B) (l, n) and (m, o)
C) (l, m) and (n, o)
D) None of the above
Answer:
D) None of the above
Question 90.
A person in a dark room looking through a window can clearly see a person outside in the daylight. But a person outside cannot see the person inside. Why does this happen ?
A) Sunlight is not as intense as all other sources of light.
B) Light rays cannot pass through the same window twice.
C) Light from outside is not able to pass through windows at all.
D) There is not enough light being reflected from the person in the room.
Answer:
D) There is not enough light being reflected from the person in the room.
Fill in the blanks.
1. Light is reflected from all ……………….. .
Answer:
surfaces
2. ……………… reflection takes place when light is incident on smooth, polished and regular surfaces.
Answer:
Regular
3. Diffused or irregular reflection takes place from …………………. surfaces.
Answer:
rough
4. The angle of incidence is …………………. the angle of reflection.
Answer:
equal to
5. Incident ray, reflected ray and the normal drawn at the point of incidence to the reflecting surface, lie in the …………………. .
Answer:
same plane
6. Image formed in …………………. undergoes lateral inversion.
Answer:
a plane mirror
7. Two mirrors inclined to each other give …………………. images.
Answer:
multiple
8. Beautiful patterns aje formed in …………………. because of multiple reflections.
Answer:
a kaleidoscope
9. …………………. called white light, consists of seven colours.
Answer:
Sunlight
10. Splitting of light into its constituent colours is known as …………………. .
Answer:
dispersion
11. Parts of the eye are …………………. .
Answer:
cornea, iris, pupil, lens, retina and optic nerve
12. A normal eye can see …………………. and ………………. objects clearly.
Answer:
nearby, distant
13. Visually impaired persons can read and write the …………………. system.
Answer:
Braille
Match the following.
Question 1.
| Group – A | Group – B |
| p) Two mirrors | 1) kaleidoscope |
| q) Three mirrors | 2) periscope |
| 3) microscope |
Answer:
p – 2, q – 1
| Group – A | Group – B |
| p) Two mirrors | 2) periscope |
| q) Three mirrors | 1) kaleidoscope |
Question 2.
| Group – A | Group – B |
| p) Cones | 1) blind spot |
| q) Rods | 2) dim light |
| 3) colours |
Answer:
p – 3, q – 2
| Group – A | Group – B |
| p) Cones | 3) colours |
| q) Rods | 2) dim light |
Question 3.
| Group – A | Group – B |
| p) Iris | 1) colour |
| q) Cornea | 2) transparent |
| 3) white |
Answer:
p – 1. q – 2
| Group – A | Group – B |
| p) Iris | 1) colour |
| q) Cornea | 2) transparent |