Wonders of Light Part – I


Wonders of Light Part – I

Q1. Fill in the blanks
1.      A ray of light parallel to principal axis after reflection from concave mirror passes through ________. (Focus)
2.      The focal length of ____________ lens is positive. (convex)
3.      The image of an object is formed behind __________ in hypermetropia. (retina)
4.      An optical device used by watch repairers is _____________. (simple microscope)
5.      The power of spectacle for myopic eye is _____________. (negative)
Q2. Rewrite the following table so as to match second and third column with first column.
Column I
Column II
Column III
1.      Myopia
Old age problem
Convex lens
2.      Hypermetropia
Near – sightedness
Bifocal lens
3.      Presbyopia
Long  - sightedness
Concave lens

1.      Myopia
Near sightedness
Concave lens
2.      Hypermetropia
Long sightedness
Convex lens
3.      Presbyopia
Old age problem
Bi-focal lens

Q3. Answer the following
1.      State the different positions of source of light with respect to concave mirror-
a.      In torches
b.      Projector lamps
c.       Flood lights.
Ans.
i.                    In torches: - The source of light is placed at the focus.
ii.                  Projector lamps: - The object is placed at the center of curvature.
iii.                Flood lights: - The source of light is placed just beyond the centre of curvature.

2.      What is ray diagram? What are the rules used for drawing ray diagrams for the formation of image by spherical mirror?
Ans.  A ray diagram is a specialized pictorial representation used to trace the path of light rays.
The rules used for drawing ray diagrams are as follows.
i.                    If the incident ray is parallel to the principal axis, then reflected ray passes through the focus.
ii.                  If the incident ray passes through the focus then the reflected ray becomes parallel to the principal axis.
iii.                If the incident ray passes through the centre of the curvature, the reflected ray traces the same path.

3.      What is meant by power of accommodation of eye?
Ans.
i.        The ability of the lens of adjusting focal length is known as power of accommodation.
ii.      The process of focusing the eye at different distances is called accommodation.  

4.      State the function of iris and ciliary muscles in human eye.
Ans.
                    I.            Iris in human eye controls and regulates the amount of light entering the eye by contracting and dialating the pupil.
                  II.            Ciliary muscles adjust the focal length of eye lens by contracting and relaxing.

5.      If you are given a part of hollow spherical glass, how will you convert it into concave mirror?
Ans. The inner side or concave side of the hollow spherical glass will be polished to get a concave mirror.

Q4. Distinguish between.
1.      Myopia and Hypermetropia
Myopia
Hypermetropia
1.      In this defect human eye can see nearby objects distinctly but is unable to see distant objects clearly.
2.      Image of distant object is formed in front of retina.
3.      Eye ball is lengthened or lens is curved.
4.      This defect is corrected using concave lens.
1.      In this defect human eye can see distant objects distinctly but is unable to see nearby objects clearly.
2.      Image of nearby objects falls behind retina.
3.      Eye ball is shortened or lens is flattened.
4.      This defect is corrected using convex lens.
2.      Convex mirror and concave mirror.
Convex mirror
Concave mirror
1.      It is called as diverging mirror.
2.      The light is reflected from outer surface.
3.      Centre of curvature and focus lies behind the mirror.
4.      According to sign convention, focal length is positive.
1.      It is called as converging mirror.
2.      The light is reflected from inner surface.
3.      Centre of curvature and focus lies in front of the mirror.
4.      According to sign convention, focal length is negative.
Q5. Give reasons:
1.      You cannot enjoy watching a movie from a very short distance from the screen in a cinema hall.
Ans.
i.                    If the object is too close, the eye lens cannot curve enough to focus the image on to the retina.
ii.                  Therefore, while watching a movie from a very short distance a blurred image is formed causing strain to the eyes.
iii.                Hence, one cannot enjoy watching a movie from a very short distance from the screen in a cinema hall.

2.      A simple microscope is used by watch repairers.
Ans.
i.                    A magnification of about 20 times is obtained by the convex lens of small focal length used in a simple microscope.
ii.                  Therefore, it is used by watch repairers to see the minute parts of the watch clearly without causing any strain to the eyes.

3.      A concave lens is used to correct myopia.
Ans.
i.                    In myopia the image of distant object is formed in front of retina.
ii.                  A concave lens causes light rays to diverge before they strike the lens of the eye so that the image is formed on the retina.
iii.                Hence, a concave lens is used to correct myopia.

4.      In old age bifocal lens is necessary for some persons.
Ans.
i.                    In old age, sometimes person suffers both myopia and hypermetropia and then the person needs bifocal lens.
ii.                  In bifocal lens, upper part is concave lens to correct myopia and lower part is convex lens to correct hypermetropia.

5.      Concave mirrors are used in solar devices.
Ans.
i.                    Concave mirrors are used in solar devices to collect heat and radiations.
ii.                  Heat radiations from the sun coming from infinity are brought to focus by concave mirror in its focal plane.
Q6. Draw well labeled ray diagrams for image formation by convex lens when
1.      Object is at 2F1.
Position of image: -At 2F2
Nature of image: - Real, Inverted and same size as that of the object.
2.      Object between F1 and 2F1
Position of image: - Beyond 2F2
Nature of image: -  Real, inverted and magnified.
3.      Object between focus F1and optical center O.
Position of image: - On the same side of the lens as the object.
Nature of image: - Virtual, erect and magnified.
Q7. Draw ray diagram for concave mirror when
1.      Object at centre of curvature.
2.      Object at focus.
3.      Object between centre of curvature and focus.
Q8. Given below is a diagram showing a defect of human eye.
Study it and answer the following questions:
1.      Name the defect shown in figure.
2.      Give two possible reasons for this defect of eye in human being.
3.      Name the type of lens used to correct the eye defect.
4.      Draw a labeled diagram to show how the defect is rectified by using the lens.
Ans.
1.      The defect of vision is hypermetropia.
2.      The two possible reasons of hypermetropia are:
a.      Weak action of ciliary muscles cause low converging power of eye lens.
b.      The distance between eye lens and retina decreases on account of either shortening of eyeball or flattening of lens.
3.      The defect is corrected using convex lens.
4.      The convex lens converges the light rays and image is now formed on the retina.
Q9. Fill in the blanks for convex lens.
0.2
0.1
P(D)
2

Ans.
0.2
0.5
0.1
P(D)
5
2
10


5
10
- 30
- 20
….
M
-2
-0.5

Ans.
15
5
10
- 30
- 20
5
M
-2
-4
-0.5


No comments:

PDF FILE TO YOUR EMAIL IMMEDIATELY PURCHASE NOTES & PAPER SOLUTION. @ Rs. 50/- each (GST extra)

HINDI ENTIRE PAPER SOLUTION

MARATHI PAPER SOLUTION

SSC MATHS I PAPER SOLUTION

SSC MATHS II PAPER SOLUTION

SSC SCIENCE I PAPER SOLUTION

SSC SCIENCE II PAPER SOLUTION

SSC ENGLISH PAPER SOLUTION

SSC & HSC ENGLISH WRITING SKILL

HSC ACCOUNTS NOTES

HSC OCM NOTES

HSC ECONOMICS NOTES

HSC SECRETARIAL PRACTICE NOTES

Balbharati Solutions for Class 12

Biology 12th Standard HSC Maharashtra State Board

Book - Keeping and Accountancy 12th Stantard HSC Maharashtra State Board

Chemistry 12th Standard HSC Maharashtra State Board

Economics HSC 12th Standard Maharashtra State Board

English Yuvakbharati 12th Standard HSC Maharashtra State Board

Geography 12th Standard HSC Maharashtra State Board

Hindi - Yuvakbharati 12th Standard Maharashtra State Board

History 12th Standard HSC Maharashtra State Board

Marathi - Yuvakbharati 12th Standard Maharashtra State Board

Mathematics and Statistics 1 (Arts and Science) 12th Standard Hsc Maharashtra State Board

Mathematics and Statistics 1 (Commerce) 12th Standard HSC Maharashtra State Board

Mathematics and Statistics 2 (Arts and Science) 12th Standard Hsc Maharashtra State Board

Mathematics and Statistics 2 (Commerce) 12th Standard HSC Maharashtra State Board

Organisation of Commerce and Management (OC) 12th Standard HSC Maharashtra State Board

Physics 12th Standard Maharashtra State Board

Political Science 12th Standard HSC Maharashtra State Board

Secretarial Practice 12th Standard HSC Maharashtra State Board

Sociology - Understanding Indian Society 12th Standard HSC Maharashtra State Board

2019 Board Paper Solution

HSC ENGLISH SET A 2019 21st February, 2019

HSC ENGLISH SET B 2019 21st February, 2019

HSC ENGLISH SET C 2019 21st February, 2019

HSC ENGLISH SET D 2019 21st February, 2019

SECRETARIAL PRACTICE (S.P) 2019 25th February, 2019

HSC XII PHYSICS 2019 25th February, 2019

CHEMISTRY XII HSC SOLUTION 27th, February, 2019

OCM PAPER SOLUTION 2019 27th, February, 2019

HSC MATHS PAPER SOLUTION COMMERCE, 2nd March, 2019

HSC MATHS PAPER SOLUTION SCIENCE 2nd, March, 2019

SSC ENGLISH STD 10 5TH MARCH, 2019.

HSC XII ACCOUNTS 2019 6th March, 2019

HSC XII BIOLOGY 2019 6TH March, 2019

HSC XII ECONOMICS 9Th March 2019

SSC Maths I March 2019 Solution 10th Standard11th, March, 2019

SSC MATHS II MARCH 2019 SOLUTION 10TH STD.13th March, 2019

SSC SCIENCE I MARCH 2019 SOLUTION 10TH STD. 15th March, 2019.

SSC SCIENCE II MARCH 2019 SOLUTION 10TH STD. 18th March, 2019.

SSC SOCIAL SCIENCE I MARCH 2019 SOLUTION20th March, 2019

SSC SOCIAL SCIENCE II MARCH 2019 SOLUTION, 22nd March, 2019

XII CBSE - BOARD - MARCH - 2019 ENGLISH - QP + SOLUTIONS, 2nd March, 2019

HSC Maharashtra Board Papers 2020

(Std 12th English Medium)

HSC ECONOMICS MARCH 2020

HSC OCM MARCH 2020

HSC ACCOUNTS MARCH 2020

HSC S.P. MARCH 2020

HSC ENGLISH MARCH 2020

HSC HINDI MARCH 2020

HSC MARATHI MARCH 2020

HSC MATHS MARCH 2020

SSC Maharashtra Board Papers 2020

(Std 10th English Medium)

English MARCH 2020

HindI MARCH 2020

Hindi (Composite) MARCH 2020

Marathi MARCH 2020

Mathematics (Paper 1) MARCH 2020

Mathematics (Paper 2) MARCH 2020

Sanskrit MARCH 2020

Sanskrit (Composite) MARCH 2020

Science (Paper 1) MARCH 2020

Science (Paper 2)


BUY FROM PLAY STORE

DOWNLOAD OUR APP


HOW TO PURCHASE OUR NOTES?



S.P. Important Questions For Board Exam 2021


O.C.M. Important Questions for Board Exam. 2021


Economics Important Questions for Board Exam 2021


Chemistry Important Question Bank for board exam 2021


Physics – Section I- Important Question Bank for Maharashtra Board HSC Examination


Physics – Section II – Science- Important Question Bank for Maharashtra Board HSC 2020 Examination


MUST REMEMBER THINGS on the day of Exam


Are you prepared? for English Grammar in Board Exam.


Paper Presentation In Board Exam


How to Score Good Marks in SSC Board Exams


Tips To Score More Than 90% Marks In 12th Board Exam


How to write English exams?


How to prepare for board exam when less time is left


How to memorise what you learn for board exam


No. 1 Simple Hack, you can try out, in preparing for Board Exam

How to Study for CBSE Class 10 Board Exams Subject Wise Tips?

JEE Main 2020 Registration Process – Exam Pattern & Important Dates

NEET UG 2020 Registration Process Exam Pattern & Important Dates

How can One Prepare for two Competitive Exams at the same time?

8 Proven Tips to Handle Anxiety before Exams!