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Ncert Exemplar Solutions Class 8 Science Light
Welcome to NCTB Solutions. Here with this post we are going to help 8th class students for the Solutions of NCERT Exemplar Class 8 Science Book, Unit 16, Light. Here students can easily find step by step solutions of all the problems for Light, Also here our Science teacher’s are solved all the questions with easily understandable language with proper guidance so that all the students can understand easily.
Light all Question Solutions :
Multiple Choice Questions :
Question no – (1)
Part of the eye which controls the light entering is called
Answer :
Correct option – (a)
Part of the eye which controls the light entering is called Iris.
Question no – (2)
We can see a non-luminous object when light
Answer :
Correct option – (b)
We can see a non-luminous object when light is reflected from the object towards our eye.
Question no – (3)
Light is falling on surface S1, S2, S3 as shown in Fig.16.1.
Answer :
Correct option – (d)
Light is falling one all the three surfaces.
Question no – (4)
A tiny mirror M is fixed on a piece of cardboard placed on a table. The cardboard is illuminated by light from a bulb. The position of eye with respect to position of bulb is shown in Fig.16.2 as A, B, C and D. In which position mirror will be visible?
Answer :
Correct option – (a) A
Figure A is representing the correct5 position.
Question no – (5)
A small hole P is made in a piece of cardboard. The hole is illuminated by a torch as shown in Fig. 16.3. The pencil of light coming out of the hole falls on a mirror.
Answer :
Correct option – (a) A
At point A the eye should be placed so that the hole can be seen.
Question no – (6)
Two mirrors A and B are placed at right angles to each other as shown in Fig.16.4.
Answer :
Correct option – (c)
The angle of reflection for the ray reflected from mirror B would be 65°
Question no – (7)
Which of the following statements is correct regarding rods and cones in the human eye?
Answer :
Correct option – (b)
Cones are sensitive to bright light – This is correct regarding rods and cones in the human eye.
Question no – (8)
In the figure of the human eye (Fig.16.5), the cornea is represented by the letter
Answer :
Correct option – (c)
In the given figure latter C represents the Cornea.
Very Short Answer Questions :
Question no – (9)
Answer :
The dark muscular structure in our eyes called Iris gives colour to our eyes.
Question no – (10)
Answer :
The image of an object stays in our eye for 1/6 th of a second so when his hand comes back and forth repeatedly in that time frame it seems to appear Blurry.
Question no – (11)
Answer :
The ray of light will reflect Unlimited Times between the two parallel mirrors which are placed facing each other.
Question no – (12)
Answer :
If the angle between the incident ray and the reflected ray is 60⁰. We could say that the angle of incidence is half the angle between incident and reflected ray. So diving 60⁰ by 2 we get 30⁰ which is the angle of incidence as well as the angle of reflection.
Question no – (13)
Answer :
In plane mirror the image formed by the mirror is at the same distance which the object is from the mirror. Here the distance between the object and the image is 24 cm. So the distance between the object and the mirror would be half of the given distance, that is 12 cm.
Short Answer Questions :
Question no – (14)
Answer :
When a light gets dispersed it separates into it’s constituents colours, that is the colour it is made up of. One very known example of this phenomenon is the formation of rainbow.
Question no – (16)
Answer :
The image of this child cannot be obtained on a screen because the images formed by a plane mirror are virtual in nature. They cannot be obtained on a screen.
Question no – (17)
Answer :
Nocturnal birds have large cornea and large pupil. These animals need to see in night conditions so this large pupil and cornea allows greater amount of lights to enter their eyes. This makes them see efficiently in dim conditions.
Question no – (18)
Answer :
Our eyes have consists of Convex lens which forms images on the layer present in the backside of our eyes commonly known as Retina.
Question no – (19)
Answer :
When someone suffers from cataract it is due a disturbance in the lens of their eyes. Cataract are commonly cured by replacing the clouded lens with a new artificial lens.
Long Answer Questions :
Question no – (20)
Answer :
(a) He need to use at least three plane mirrors to see the object.
(c) He should place the mirrors at 45⁰ of angle with respect to the incident ray.
(e) He will not be able an image if any one of the mirror is removed because the ray must reflect from every mirror to reach his eyes.
Question no – (21)
Answer :
The cartoon films that we see are nothing but pictures that are moving at a very fast rate. Since a picture stays in our eyes for 1/6th of a second and as these pictures appears before our eyes at a rate of 24 pictures per second, that is much faster than the persistence of an image in our eyes, we perceive it as a motion or a video.
Question no – (22)
Answer :
A kaleidoscope is made up of plane mirrors which are attached in such a way that it makes a prism. It performs on the principle of multiple image formation, that is the light from the object gets reflected between the multiple mirrors which are placed in a certain positions and angle. This results in the formation of different images or pattern of the object that is being reflected.
A kaleidoscope is used for many purposes. Wallpapers and fabric designers often use these kaleidoscope to find out some interesting design and patterns that can be used for our clothes or walls designing.
Other Chapter Solutions :
👉 Crop Production and Management
👉 Microorganisms : Friend and Foe
👉 Synthetic Fibres and Plastics
👉 Materials : Metals and Non-Metals
👉 Conservation of Plants and Animals
👉 Cell-Structure and Functions
👉 Reaching the Age of Adolescence
👉 Force
👉 Friction
👉 Sound
