NCERT Solutions for Class 8 Science Chapter 16 – Light
Orchid International School is pleased to offer the PDF download of NCERT Solutions for Class 8 Physics Chapter 16. These solutions are readily accessible on our official website. By downloading the PDF, you can access comprehensive NCERT Solutions, enabling you to thoroughly review Class 8 Science Chapter 16.
Download PDF For NCERT Solutions for Science Light
The NCERT Solutions for Class 8 Science Chapter 16 – Light are tailored to help the students master the concepts that are key to success in their classrooms. The solutions given in the PDF are developed by experts and correlate with the CBSE syllabus of 2023-2024. These solutions provide thorough explanations with a step-by-step approach to solving problems. Students can easily get a hold of the subject and learn the basics with a deeper understanding. Additionally, they can practice better, be confident, and perform well in their examinations with the support of this PDF.
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Access Answers to NCERT Solutions for Class 8 Science Chapter 16 – Light
Students can access the NCERT Solutions for Class 8 Science Chapter 16 – Light. Curated by experts according to the CBSE syllabus for 2023–2024, these step-by-step solutions make Science much easier to understand and learn for the students. These solutions can be used in practice by students to attain skills in solving problems, reinforce important learning objectives, and be well-prepared for tests.
Light
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room? Explain.
In a dark room, one cannot see things in a room, but things outside the room will be visible.
Differentiate between regular and diffused reflection. Does diffused reflection mean the failure of the laws of reflection?
The difference between regular and diffused reflection is as follows:
|
Regular Reflection |
Diffused Reflection |
|
Regular Reflection takes place from a smooth and shiny surface. |
Diffused Reflection takes place on a rough or irregular surface. |
|
All rays are parallel after reflection. |
The reflected rays are not parallel to each other. |
Diffused reflection is not due to the failure of the laws of reflection. It is caused by irregularities in the reflecting surface.
Mention against each of the following whether regular or diffused reflection will take place when a beam of light strikes. Justify your answer in each case.
a. Polished wooden table
b. Chalk powder
c. Cardboard surface
d. Marble floor with water spread over it
e. Mirror
f. Piece of paper
a . A polished surface means the surface is very smooth, thus
regular reflection takes place.
b . A diffused reflection takes place on a chalk powder because its surface is uneven.
c . The surface of cardboard that reflects light is not smooth, thus diffused reflection will take place from a cardboard surface.
d .The water spread over marble makes the surface very
Smooth which makes it act like a plane surface. Hence, regular reflection takes place.
e .The surface of the mirror is very smooth and shiny. Therefore, regular reflection takes place.
f . A piece of paper may look smooth, but it has many irregularities on its surface. Thus, diffused reflection takes place.
State the laws of reflection.
Laws of reflection can be stated as follows:
-
The angle of reflection and angle of incidence is always equal to each other.
-
The incident ray, the normal at the point of incidence and the reflected ray all lie in the same plane.
Describe an activity to show that the incident ray, the reflected ray and the normal at the point of incidence lie in the same plane.
To perform this experiment take a plane mirror and place it on a plane sheet of paper in a standing position with a block. Then draw an incidence line AB on this paper. Mark the points on the paper by carefully looking at the mirror. The line that goes after it appears on the screen. Draw a perpendicular on the mirror line and then remove the mirror. Join the points to make the reflected ray on the paper. You will observe that incident ray, reflected ray and normal will be in the same plane, i.e. on the sheet of paper. This verifies the law of reflection.
Fill in the blanks in the following.
a. A person
1
1
m in front of a plane mirror seems to be ____ m away from his image.
b. If you touch your ________ ear with your right hand in front of a plane mirror, it will be seen in the mirror that your right ear is touched with your _________.
c. The size of the pupil becomes ________ when you see in dim light.
d. Night birds have _________ cones than rods in their eyes.
a . A person
1
1
m in front of a plane mirror seems to be
2
2
m away from his image.
b . If you touch your left ear with your right hand in front of a plane mirror, it will be seen in the mirror that your right ear is touched with your left hand.
c . The size of the pupil becomes large when you see it in dim light.
d . Night birds have lesser cones than rods in their eyes.
The angle of incidence is equal to the angle of reflection.
a. Always
b. Sometimes
c. Under special conditions
d. Never
(a) Always
Since the first law of reflection states that the angle of incidence and
the angle of reflection is always equal to each other.
The image formed by a plane mirror is
a. Virtual, behind the mirror and enlarged.
b. Virtual, behind the mirror and of the same size as the object.
c. Real at the surface of the mirror and enlarged.
d. Real, behind the mirror and of the same size as the object.
b. Virtual, behind the mirror and of the same size as the object.
The image created by the plane mirror is built behind the mirror. This image cannot be created on screen, so it produces a virtual image of the size that of the object.
Describe the construction of a kaleidoscope.
The Kaleidoscope is made up of three rectangular squares each about
15
15
cm long and
4
4
cm wide which are joined together to build a prism. They are arranged in a circular cardboard tube. Note that the tube is slightly longer than the screen straps. One end of the tube is closed with a cardboard disc with a hole in the middle. To make the disk last longer, a piece of transparent plastic paper is attached to the bottom of the cardboard disk. At the other end, a round plate of the glass plane is fixed touching the mirrors.
Draw a labelled sketch of the human eye.
Gurmit wanted to perform Activity
using a laser torch. Her teacher advised her not to do so. Can you explain the basis of the teacher’s advice?
The intensity of the laser light is very high which is harmful to the eye and can cause a permanent defect in the eye. She can lose her eyesight also due to severe damage to the retina. Therefore, it is advisable not to look at a laser beam directly.
Explain how you can take care of your eyes.
To protect our eyes, the following precautions should be taken:
i. Do not read in too little or too much light.
ii. Wash your eyes frequently with cold water.
iii. Do not read by bringing your book too close to your eyes or keeping it too far.
iv. Never rub your eyes.
v. If particles of dust go into our eyes, wash our eyes with clean water. If there is no improvement go to a doctor.
What is the angle of incidence of a ray if the reflected ray is at an angle of
90∘
90∘
to the incident ray?
Ans: We know that angle of incidence is equal to the angle of reflection. Therefore, twice of incidence angle is equal to
90∘
90∘
.
Thus, Angle of incidence
i=
90
∘
2
�=90∘2
.
⇒i=
45
∘
⇒�=45∘
How many images of a candle will be formed if it is placed between two parallel plane mirrors separated by 40 40
cm?
Since the mirrors are kept parallel to each other, and Infinite no of images will be formed due to multiple reflections between them.
Two mirrors meet at right angles. A ray of light is incident on one at an angle of
30∘
30∘
as shown in Fig.
16.19
16.19
. Draw the reflected ray from the second mirror.
From the first law of reflection, The angle of reflection and angle of incidence is always equal to each other.
The diagram of the reflected ray from the second mirror is as follows:
Boojho stands at
A
�
just on the side of a plane mirror as shown in Fig.
16.20
16.20
. Can he see himself in the mirror? Also, can he see the image of objects situated at
P,Q,R
�,�,�
?
A
�
cannot see his image as the length of the mirror is too short on his side. He can see the image of the objects at
P
�
and
Q
�
but cannot see the object at
R
�
as can be inferred from the ray diagram.
Solve the below referring to the given diagram.
a. Find out the position of the image of an object situated at
A
�
in the plane mirror.
b. Can Paheli at
B
�
see this image?
c. Can Boojho at
C
�
see this image?
d. When Paheli moves from
B
�
to
C
�
, where does the image of
A
�
move?
a . The image of
A
�
is formed behind the mirror at the same distance as that of
A
�
from the mirror.
b . Yes, Paheli at
B
�
can see the image.
c . Yes, Boojho at
C
�
can see the image.
d . The image of
A
�
is unaffected by the movement of
B
�
and
C
�
. Therefore, Paheli will be able to see the image of
A
�
while moving from
B
�
to
C
�
Frequently Asked Questions
The NCERT solution for Class 8 Chapter 16 : Light is important as it provides a structured approach to learning, ensuring that students develop a strong understanding of foundational concepts early in their academic journey. By mastering these basics, students can build confidence and readiness for tackling more difficult concepts in their further education.
Yes, the NCERT solution for Class 8 Chapter 16 : Light is quite useful for students in preparing for their exams. The solutions are simple, clear, and concise allowing students to understand them better. They can solve the practice questions and exercises that allow them to get exam-ready in no time.
You can get all the NCERT solutions for Class 8 Science Chapter 16 from the official website of the Orchids International School. These solutions are tailored by subject matter experts and are very easy to understand.
Yes, students must practice all the questions provided in the NCERT solution for Class 8 Science Chapter 16 : Light as it will help them gain a comprehensive understanding of the concept, identify their weak areas, and strengthen their preparation.
Students can utilize the NCERT solution for Class 8 Science Chapter 16 effectively by practicing the solutions regularly. Solve the exercises and practice questions given in the solution.