### Wonders of light – part II

Wonders of light – part II

Q1. Fill in the blanks
1.      The phenomenon of splitting of light into its component colours is ____________ (dipersion)
2.      Very fine particles mainly scatter ___________ light. (blue)
3.      The phenomenon of change in the ___________ of light when it passes from one transparent medium to another is refraction. (direction)
4.      The refractive index depends upon the ___________ of propagation of light in different media. (relative speed)
Q2. Rewrite the following table in such a way that column 2 and column 3 matches column 1.
 Column 1 Column 2 Column 3 Dispersion Change in the direction of ray of light due to change in medium. Blue colour of the sky. Scattering Splitting of white light into component colours Twinkling of stars. Refraction Deflection of light by small particles Spectrum of seven colours.

Ans.
 Column 1 Column 2 Column 3 Dispersion Splitting of white light into component colours Spectrum of seven colours. Scattering Deflection of light by small particles Blue colour of the sky. Refraction Change in the direction of ray of light due to change in medium. Twinkling of stars.

1.      What do you mean by dispersion? Name the different colours of light in the proper sequence in the spectrum of light.
Ans.
i.                    The phenomenon of splitting of white light into its component colours is dispersion.
ii.                  The various colours in the spectrum of light are in the sequence:  Violet, indigo, Blue, Green, Yellow, Orange and Red.
2.      Explain how the formation of rainbow occurs.
Ans.

1.      The beautiful phenomenon of the rainbow is a combination of different phenomena – dispersion, refraction and reflection of light.
2.      The rainbow appears in the sky after a rain shower.
3.      The water droplets act as a small prisms.
4.      When sunlight enters the water droplets present in the atmosphere, they refract and disperse the incident sunlight.
5.      Then they reflect it internally inside the droplet and finally again refract it.
6.      As a collective effect of all the phenomena, the seven coloured rainbow is observed.

3.      What is refraction of light? How is it related to refractive index?
Ans.
i.                    The phenomenon of change in the direction of light when it passes from transparent medium to another is called dispersion of light.
ii.                  The extent of change in the direction of the light ray is different for different media and it is related to the refractive index of the medium.

Q4. Give reasons.
1.      The sky appears dark instead of blue to a person located in space.
Ans.
i.                    At very high altitudes, there is no atmosphere.
ii.                  Since there is no atmosphere, the scattering of light does not take place at all.
iii.                Hence, the sky appears dark instead of blue to a person located in space.

2.      Stars twinkle at night.
Ans.
i.                    In the atmosphere, there are different layers of air with different refractive indices which keep on changing.
ii.                  When we observe the stars through this air the light coming from them refract randomly so that the intensity of light varies due to which the apparent position of the star fluctuates.
iii.                When more light reaches our eyes the star is seen bright and when less light reaches our eyes, the star is seen dim.
iv.                 Thus, due to change in refractive index of atmosphere, stars appear twinkling at night.

3.      The sun appears reddish early in the morning.
Ans.
i.                    At the time of sunrise, the blue and violet colours are scattered away from the path of sunlight as thickness of the atmosphere is more between the horizon and the observer.
ii.                  The light that reaches to the observer is mostly red.
iii.                Hence the sun appears reddish early in the morning.

4.      It is possible to enjoy a rainbow at fountains in any season.
Ans.
i.                    One can observe and enjoy the rainbow by standing in front of a water fountain in the evening facing the east.
ii.                  One can also enjoy it in the morning under the same conditions just by facing the west.
iii.                Therefore, it is possible to enjoy a rainbow at fountains in any season.

Q5. Write short notes on
1.      Refraction observed in the atmosphere.
Ans.
i.                    In the atmosphere, there are different layers of air with different refractive indices which keep on changing as the physical conditions of air are not stationary (still).
ii.                  When we observe any object through this air, the light coming from them refract randomly due to which the apparent position of the object fluctuates.
iii.                The large scale effect of this phenomenon is the twinkling of stars, advanced sunrise and delayed sunset.
iv.                 Due to change in the refractive index of atmosphere, the intensity of light that reaches our eyes from the stars varies and hence the stars appear twinkling at night.
v.                   Advanced sunrise occurs as a ray of light from the sun enters the earth’s atmosphere; it follows a curved path due to refraction before reaching to the observer.
vi.                 It appears to the observer as if the rays are coming from the position where the sun is seen by the observer, hence, the sun is seen earlier before it reaches the horizon.

2.      Dispersion of light.
Ans.
i.            The phenomenon of splitting of light into its component colours is dispersion of light.
ii.            The band of coloured components of a light beam is called it’s spectrum.
iii.            When White light is dispersed into seven colours by a prism, different colours of light bend through different angles with respect to incident ray.
iv.            Out of these seven colours, red light bend the least while violet light bends the most.
v.            So the rays of each colour emerge along different paths and become distinct.
Hence we get a spectrum of seven different colours in the sequence, Violet, Indigo, Blue, Green, Yellow, Orange and Red.

# 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)

HOW TO PURCHASE OUR NOTES?

S.P. 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!