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ASSIGNMENT BOOKLET
Bachelor's Degree Programme (B.Sc.)
ASTRONOMY AND ASTROPHYSICS
School of Sciences
Indira Gandhi National Open University Maidan Garhi, New Delhi-110068
(2012)
PHE-15
Please send this assignment to:
Prof. Vijayshri Course Coordinator, PHE-15, School of Sciences, IGNOU,
Room No. 128, Block D, New Academic Complex
NEW DELHI 110068
Please Note
• You can take electives (56 to 64 credits) from a minimum of TWO and a
maximum of FOUR science disciplines, viz. Physics, Chemistry, Life
Sciences and Mathematics.
• You can opt for elective courses worth a MINIMUM OF 8 CREDITS and a
MAXIMUM OF 48 CREDITS from any of these four disciplines.
• At least 25% of the total credits that you register for in the elective
courses from Life Sciences, Chemistry and Physics disciplines must be
from the laboratory courses. For example, if you opt for a total of 64
credits of electives in these 3 disciplines, at least 16 credits should be
from lab courses.
• You cannot appear in the Term-End Examination of any course without
registering for the course. Otherwise, your result will not be declared
and the onus will be on you.
It is compulsory to submit the Assignment before filling in the
Term-End Examination Form.
Valid from January 1, 2012 to December 31, 2012
2
Dear Student, We hope you are familiar with the system of evaluation to be followed for the Bachelor’s Degree Programme. At this stage you may probably like to re-read the section on assignments for Elective Courses in the Programme Guide that we sent you after your enrolment. A weightage of 30 per cent, as you are aware, has been earmarked for continuous evaluation which would consist of one tutor-marked assignment (TMA) for this course. Instructions for Formatting your Assignment
Before attempting the assignment please read the following instructions carefully: 1) On top of the first page of your TMA answer sheet, please write the details exactly in the following
format:
ENROLMENT NO.:……………………………………………
NAME :……………………………………………
ADDRESS :……………………………………………
……………………………………………
…………………………………………… COURSE CODE: …………………………….
COURSE TITLE : …………………………….
ASSIGNMENT NO. ………………………….…
STUDY CENTRE: ………………………..….. DATE:.…………………………………...
PLEASE FOLLOW THE ABOVE FORMAT STRICTLY TO FACILITATE EVALUATION AND
TO AVOID DELAY.
2) Use only foolscap size writing paper (but not of very thin variety) for writing your answers.
3) Leave 4 cm margin on the left, top and bottom of your answer sheet.
4) Your answers should be precise.
5) While solving problems, clearly indicate the question number along with the part being solved. Be precise. Write units at each step of your calculations as done in the text because marks will be deducted for such mistakes. Take care of significant digits in your work. Recheck your work before submitting it.
6) This assignment will remain valid from January 1, 2012 to December 31, 2012. However, you are advised to submit it within 12 weeks of receiving this booklet to accomplish its purpose as a teaching-tool. Answer sheets received after the due date shall not be accepted.
We strongly feel that you should retain a copy of your assignment response to avoid any
unforeseen situation and append, if possible, a photocopy of this booklet with your response.
We wish you good luck.
3
Tutor Marked Assignment
Astronomy and Astrophysics (PHE-15)
Course Code: PHE-15
Assignment Code: PHE-15/2012
Max. Marks: 100
Note: You must write answers in your own words. DO NOT reproduce from your study material.
1. a) Express the distances of the stars Sirius B and Antares from the Earth in light years. (5)
b) Compare the brightness of the stars Sirius B and Sirius A using the data given in Table 1.3. (5)
c) The zenith distance of a star at latitude 30° N is 25°. Calculate its declination. (5)
d) The local time at Chennai is 8 p.m. Calculate the local time at New Delhi at that time. (5)
e) Calculate the magnitude of the faintest object that a 1 m telescope can detect. (5)
2. a) Explain why the temperature of sunspots is lower than their surroundings. What is the butterfly diagram? (3+2)
b) Discuss the three stages of the formation of planets from the solar nebula. (5)
c) Explain the atomic origin of emission and absorption spectra. (5)
d) Write down the order of magnitude by which the internal temperature of the Sun is higher than its surface temperature. Explain the energy generation process at the core of a star. (1+4)
e) Show that for a polytrop,
1+θ= n
cPP
where Pc is central pressure and n is polytropic index. (5)
3. a) Explain the free fall collapse of an interstellar cloud? Show that the free fall time of a collapsing cloud is a function of the initial density of the cloud. (1+4)
b) What is cosmic abundance? How does it relate to the solar system abundance? How do you differentiate between population I and population II stars? (2+1+2)
c) What is planetary nebula? Explain the concept of Chandrasekhar limit. (2+3)
d) The mass and radius of a neutron star is 2MΘ and 15 km, respectively. Calculate the value of gravitational red shift for light of wavelength 6000 Å at a distance of 2 m from its surface. (5)
e) Explain the difference between rigid body rotation and Keplerian motion. What is galactic longitude? (4+1)
4. a) Explain Hubble’s scheme of galaxy classification. Why has this scheme proved enduring? What class has been assigned to the Milky Way Galaxy? (5+3+2)
b) With the help of a diagram, explain the unified scheme for understanding active galactic nuclei. (10)
c) Explain how Cepheid variables can be used to measure astronomical distances. (5)
4
2. a) What do you understand by solar activity? Discuss three solar activities. (1 + 3 + 3 + 3)
b) Assume that the star Proxma Centrauri radiates like a black body. Calculate its temperature. For Proxima Centauri, take radius R = 5 × 10−24 W. (7)
c) Discuss the contribution of M.N. Saha in spectral classification. Explain how H-R diagram gives important information about a star. (4 + 4)
3. a) What do you understand by Jeans criterion? Derive expressions for Jeans mass and Jeans radius. (3 + 5 + 2)
b) Discuss the three major processes by which elements are synthesised in the stellar core. Why does the synthesis process end at iron? (3 + 3 + 3 + 1)
c) The luminosity of a white dwarf star of mass 1.2 MΘ is 10−2.5 LΘ. If the luminosity of the Sun, LΘ is 4 × 1026 J s−1, calculate the time for which the white dwarf will keep shining with its present luminosity. (5)
5
TENTATIVE SCHEDULE FOR PHYSICS PROGRAMMES BROADCAST
ON GYAN DARSHAN 1
January 2012 – December 2012 This is the tentative schedule for Physics students. The students may approach their cable operator to avail this facility. Date/Day Time Slot Course Code Video Programme Title
January 2012
08-01-12 (Sun)
9.00–9.30 pm PHE-15 Glimpses of the Cosmos
15-01-12 (Sun)
9.00–9.30 pm PHE-02 Simple Harmonic Motion
22-01-12 (Sun)
9.00–9.30 pm PHE-15 Exploring the Night Sky
24-01-12 (Tues)
8.30-9.00 am PHE-02 Dolan
February 2012
12-02-12 (Sun)
9.00–9.30 pm PHE-15 On the Trail of Stars
14-02-12 (Tues)
8.30-9.00 am PHE-06 Second Law of Thermodynamics
21-02-12 (Tues)
8.30-9.00 am PHE-02 Coupled Oscillations
March 2012
06-03-12 (Tues)
8.30-9.00 am PHE- 13 Introduction to Crystal Structure
13-03-12 (Tues)
8.30-9.00 am PHE- 15 Astronomical Coordinates
18-03-12 (Sun)
9.00–9.30 pm PHE- 10 Operational Amplifier
20-03-12 (Tues)
8.30-9.00 am PHE- 06 Carnot Cycle
April 2012
08-04-12 (Sun)
9-00-9.30 pm PHE- 15 Astronomical Measurements (Measurement of Distance and Brightness)
15-04-12 (Sun)
9-00-9.30 pm PHE- 01 Rotating Frames of Reference
May 2012
13-05-12 (Sun)
9.00-9.30 pm PHE -15 Astronomical Measurements (Measurement of Mass, Temperature and Time)
15-05-12 (Tues)
8.30-9.00 am PHE -10 Logic Gates
6
Date/Day Time Slot Course Code Video Programme Title
July 2012
08-07-12 (Sun)
9.00-9.30 pm PHE-04 Vector Calculus Part-I
10-07-12 (Tues)
8.30-9.00 am PHE-01 Exploring Physics: Experiment with Low cost Materials
15-07-12 (Sun)
9.00-9.30 pm LT- 04 Physics Lab Technician: Know your job
22-07-12 (Sun)
9.00-9.30 pm LT- 04 Bhautiki Prayogshala Technician: Aapka Kaam
24-07-12 (Tues)
8.30-9.00 am PHE-01 The Bicycle: A Vehicle for Teaching Physics
August 2012
07-08-12 (Tues)
8.30-9.00 am PHE- 01 The Physics of Dance
14-08-12 (Tues)
8.30-9.00 am PHE- 15 The Milky Way
21-08-12 (Tues)
8.30-9.00 am PHE -04 Vector Calculus Part-II
28-08-12 (Tues)
8.30-9.00 am PHE- 15 Stellar Spectra and Classification
September 2012
04-09-12 (Tues)
8.30-9.00 am PHE- 10 Digital Modulation
09-09-12 (Sun)
9.00-9.30 am PHE -10 Amplitude Modulation
11-09-12 (Tues)
8.30-9.00 am PHE- 06 First Law of Thermodynamics
October 2012
07-10-12 (Sun)
9.00–9.30 pm PHE-06 Applications of the First Law of Thermodynamics
14-10-12 (Sun)
9.00–9.30 pm PHE-15 Stellar Structure
November 2012
11-11-12 (Sun)
9.00–9.30 pm PHE-10 Transistor Biasing
December 2012
16-12-12 (Sun)
9.00–9.30 pm PHE-06 Thermodynamics in Action
18-12-12 (Tues)
8.30-9.00 am PHE-06 Ushmagatiki ke Anuprayog
25-12-12 (Tues)
8.30-9.00 am PHE-10 Electronic Device
7
TENTATIVE SCHEDULE FOR PHYSICS STUDENTS ON DD1 (National Network)
JANUARY 2012 TO NOVEMBER 2012
Time: 6.00 AM to 6.30 AM
Month/Date* Course Topic
January 2012
09-01-12
PHE-13 Introduction to Crystal Structure
February 2012
13-02-12
PHE-01 Ghurni Nirdesh Tantra (Hindi)
March 2012
12-03-12
PHE-15 The Milky Way
April 2012
09-04-12
PHE-10 Semiconductor Diode
May 2012
14-05-12
PHE-15 On the Trail of Stars
July 2012
09-07-12
PHE-10 Operational Amplifier
August 2012
13-08-12
PHE-02 Coupled Oscillations
September 2012
10-09-12
PHE-10 Transistor Configuration
October 2012
08-10-12
PHE-06 Thermodynamics in Action
November 2012
12-11-12
PHE-15 Exploring the Night Sky
* Second Monday of every month
8
Dear Student,
We would like to get your feedback on the course Astronomy and Astrophysics (PHE-15) while you are studying it. Fill in your answers about each unit while you are studying/revising it.
THIS FEEDBACK IS COMPULSORY AND YOU MUST SEND IT TO US.
Please keep a copy of your assignment with you for the sake of record.
Do not give incorrect information just to please us. Your answers should be based on your own experience, good or bad; pleasant or otherwise.
PLEASE POST YOUR FEEDBACK AND THE ASSIGNMENT RESPONSE OF PHE-15 TO US.
If you face any difficulty regarding the course, please feel free to contact us on our e-mails: vijayashri@ignou.ac.in, srjha@ignou.ac.in.
We wish you all the very best.
(Vijayshri)
Course Coordinator, PHE –15
School of Sciences, IGNOU
Room no. 128, Raman Block,
New Academic Complex
Maidan Garhi
New Delhi – 110068
9
FEEDBACK ON “ASTRONOMY AND ASTROPHYSICS” (PHE-15)
Tick (√√√√) the appropriate responses, wherever needed.
1. a. Name : …………………………………… b. Male / Female
c. Enrolment Number: ………………………. d. Date of birth : ………………
e. Study Centre Code and Name .…………………………...
2. Do you have access to Internet? At home / Yes, at a friend’s home / Yes, at cyber café / Yes, at study centre / No
If yes, write your e-mail address: ..........................................................................................
3. Are you doing B.Sc. Major in Physics? Yes/No.
a) If not, please list the Physics electives you have opted for in B.Sc.
………………………………………………………………………………………………
………………………………………………………………………………
4. List the electives that you have taken from other disciplines.
………………………………………………………………………………………………………
………………………………………………………………………………………………………
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5. Rate your proficiency in English: Very good/ good/ fair/ average/ not so good
6. Are you employed? Yes/No.
If yes, please specify the nature of the employment
………………………………………………………………………………………………………
………………………………………………………………………………………………………
7. Did you study the course introduction and block introductions before studying the units.
Yes/No.
a) If yes, do you have any suggestions about their content, length, language, etc.
………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………
8. Did you read the introduction and objectives of each Unit before studying it? Yes/No.
9. Are the introduction and objectives of the Units clear to you? Yes/No.
10
If not, specify the difficulties:
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
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10. Put a tick mark on the correct response:
(i) The level of the course was as I expected.
Yes/No, it was too high/ No, it was lower.
(ii) The topics, concepts covered were interesting and informative.
Yes /No
(iii) The mathematics used was as I expected.
Yes/No, it was Difficult/No, it was easy
(iv) I would have preferred a non-mathematical explanation. Yes /No
11. Would you like:
(i) to attend radio counseling for the course? Yes /No
If yes, please mention the preferred timings
(ii) to attend teleconferencing for the course? Yes /No
If yes, please mention the preferred timings.
(iii) your difficulties to be solved through letters from counsellors.
Yes /No
(iv) to use the INTERNET facilities for counseling. Yes /No
12. Do you use computer for study purpose? Yes/No
If yes, which software packages do you use?
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
11
13. Your overall comments on the course. (Write the comments on the course after studying it.) You may use extra pages.
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
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14. Please fill the enclosed annexure to give us unit-wise feedback.
15. If you have filled in words like 'not clear/difficult/not sufficient/not interesting', etc. in any of the rows and columns for the units in Annexure, please mention what is not clear about each part. Use additional pages if need be.
………………………………………………………………………………………………………
………………………………………………………………………………………………………
……………………………………………………………………………………………………
16. What (e.g., explanation, diagram, examples, definitions, etc.) would you like to be added or deleted in the units to make it easier to study? Use additional pages if your answer is long.
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
17. Have you received teaching comments from counsellors on your TMA responses
for other physics electives that can help you in learning the concepts better? Yes/No
If yes, please list all such TMAs.
………………………………………………………………………………………………………
………………………………………………………………………………………………………
12
ANNEXURE
4. Unit wise Feedback : Answer this part while studying each unit or immediately afterwards.
Note : Please tell us about your difficulties in studying each section of the units. To describe your response, you may select the appropriate words from among the following : not clear, not sufficient, difficult, not relevant, not interesting. If you wish, you can use any other words. For example, if you feel that the language used in Sec. 1.2 is difficult and not clear, you should write the words ‘difficult, not clear’ at *. In the last
column, you have to tell the approximate time you have taken to study each section.
Block 1 Unit 1 : Astronomical Scales
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the
section (min./h.)
1.2 *
1.3
1.4
1.4.1
1.4.2
1.4.3
1.4.4
13
Block 1 Unit 2 : Basic Concepts of Positional Astronomy
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
2.2
2.2.1
2.2.2
2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.4
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
14
Block 1 Unit 3 : Astronomical Techniques
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.3
3.3.1
3.3.2
3.3.3
3.4
3.4.1
3.4.2
15
Block 1 Unit 4: Physical Principles
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
4.2
4.2.1
4.2.2
4.3
4.4
4.4.1
4.4.2
4.4.3
4.4.4
16
Block 2 Unit 5 : The Sun
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
5.2
5.3
5.4
5.4.1
5.4.2
5.5
5.6
5.7
Block 2 Unit 6 : The Solar Family
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
6.2
6.3
6.4
6.5
17
Block 2 Unit 7: Stellar Spectra and Classification Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
7.2
7.3
7.3.1
7.3.2
7.4
7.5
Block 2 Unit 8: Stellar Structure
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
8.2
8.3
8.4
8.5
8.6
8.6.1
18
Block 3 Unit 9 : Star Formation Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
9.2
9.2.1
9.2.2
9.3
9.3.1
9.3.2
9.4
9.4.1
Block 3 Unit 10: Nucleosynthesis and Stellar Evolution Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
10.2
10.3
10.4
10.4.1
10.4.2
10.5
19
Block 3 Unit 11: Compact Stars Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
11.2
11.2.1
11.3
11.3.1
11.4
11.4.1
11.4.2
11.5
11.5.1
20
Block 3 Unit 12: The Milky Way Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
12.2
12.3
12.3.1
12.3.2
12.3.3
12.4
12.5
21
Block 4 Unit 13: Galaxies
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
13.2
13.2.1
13.3
13.3.1
13.3.2
13.3.3
13.4
13.4.1
13.4.2
13.4.3
13.4.4
13.5
13.6
13.7
22
Block 4 Unit 14 : Active Galaxies
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
14.2
14.2.1
14.2.2
14.2.3
14.3
14.3.1
14.3.2
14.3.3
14.4
14.4.1
23
Block 4 Unit 15: Large Scale Structure and The Expanding Universe
Section Explanation of
Concepts
Examples
given
Language
used
Mathematics
used
Technical
Definitions
Figures and
Tables
SAQs and
Terminal
Questions
Time taken to
study the section
(min./h.)
15.2
15.2.1
15.2.2
15.3
15.3.1
15.4
15.4.1
15.5
15.6
15.6.1
15.6.2
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