ASSIGNMENT BOOKLET Bachelor's Degree Programme PHE-15 ASTRONOMY AND ASTROPHYSICS Valid from July 1, 2011 to March 31, 2012 It is compulsory to submit the Assignment before filling in the Term-End Examination Form. 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. 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. Please send your assignment response and feedback to: Prof. Vijayshri Course Coordinator, PHE-15 School of Sciences, Room No. 128, Block D, New Academic Complex IGNOU, Maidan Garhi, NEW DELHI 110068 School of Sciences Indira Gandhi National Open University Maidan Garhi, New Delhi-110068 (For July, 2011 Cycle)
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 and in your own words. Do not copy answers from study material. 5) While solving problems, clearly indicate the question number along with the part being solved. 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 July 1, 2011 to March 31, 2012. However, you are advised to submit it within 12 weeks of receiving this booklet to accomplish its purpose as a teaching-tool. 7) A feedback form is being sent along with this assignment. PLEASE FILL IT UP AND POST IT TO US. 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. If you have any problems or queries related to the course, you can write to us on the e-mail vijayashri@ignou.ac.in. We wish you good luck. 2
Tutor Marked Assignment PHE-15: Astronomy and Astrophysics Course Code: PHE-15 Assignment Code: PHE-15/TMA/2011-12 Max. Marks: 100 Note: Answer in your own words. DO NOT COPY FROM THE COURSE MATERIALS. The marks for each question are indicated against it. Symbols have their usual meanings. 1. (a) Express the distances of planet Pluto from the Earth in light year and parsec and the star Proxima Centauri from the Sun in AU and parsec. (10) (b) Draw the celestial sphere showing the observer s meridian, zenith, celestial equator and the horizon for an observer at latitude 30 N. Show the horizon coordinates of a star X on the celestial sphere for this observer. Would these coordinates be the same at latitude 60 N? (5 + 4 + 1) (c) Which telescope, optical or X-ray, would have higher resolving power for the same aperture? Calculate the magnitude of the faintest object that a 1 m optical telescope can detect. (2+3) 2. (a) How does the radiation generated in the Sun s interior differ from the radiation we receive from the Sun s surface? What is the reason for it? Explain why the temperature of sunspots is lower than their surroundings. (2+3+3) (b) The temperature inside a sunspot is 400 K and that of its surrounding is 6000 K. Calculate the strength of the magnetic field inside the sunspot which will balance the pressure inside and outside. (5) (c) Discuss the formation of nebular disk and the three stages of the formation of planets from the solar nebula. (3+4) (d) Discuss the contribution of M.N. Saha in the classification of stars. Explain with an example. (5) 3. (a) What are the constituents of interstellar medium? What is the significance of 21-cm radiation in the study of ISM? How is the 21-cm radiation produced? Why is it not possible to produce 21-cm radiation in the laboratory? (2+2+3+3) (b) The estimated lifetime of the Sun on the main sequence is ~ 10 10 years. Calculate the main sequence lifetime of a star of mass 2 M Θ. (5) (c) Suppose a collapsing cloud is made of neutral hydrogen (HI) only. Calculate its Jeans mass taking its temperature as 60K and its number density as 900 m 3. (5) (d) What is the Chandrasekhar limit? Discuss the evolution of stars whose masses are beyond the Chandrasekhar limit. (5) 4. (a) Describe the classification of active galaxies. (10) (b) Explain Hubble s classification of galaxies. (10) (c) Explain the concept of cosmic distance ladder. (5) 3
TENTATIVE SCHEDULE FOR PHYSICS PROGRAMMES BROADCAST ON GYAN DARSHAN 1 July 2011 May 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 July 2011 10-07-11 12-07-11 17-07-11 24-07-11 26-07-11 August 2011 09-08-11 16-08-11 23-08-11 23-08-11 9.00-9.30 pm PHE-04 Vector Calculus Part-I 8.30-9.00 am PHE-01 Exploring Physics: Experiment with Low cost Materials 9.00-9.30 pm LT- 04 Physics Lab Technician: Know your job 9.00-9.30 pm LT- 04 Bhautiki Prayogshala Technician: Aapka Kaam 8.30-9.00 am PHE-01 The Bicycle: A Vehicle for Teaching Physics 8.30-9.00 am PHE- 01 The Physics of Dance 8.30-9.00 am PHE- 15 The Milky Way 8.30-9.00 am PHE -04 Vector Calculus Part-II 8.30-9.00 am PHE- 15 Stellar Spectra and Classification September 2011 06-09-11 8.30-9.00 am PHE- 10 Digital Modulation 11-09-11 9.00-9.30 am PHE -10 Amplitude Modulation 13-09-11 8.30-9.00 am PHE- 06 First Law of Thermodynamics October 2011 09-10-11 9.00 9.30 pm PHE-06 Applications of the First Law of Thermodynamics 16-10-11 9.00 9.30 pm PHE-15 Stellar Structure November 2011 13-11-11 9.00 9.30 pm PHE-10 Transistor Biasing December 2011 18-12-11 9.00 9.30 pm PHE-06 Thermodynamics in Action 20-12-11 8.30-9.00 am PHE-06 Ushmagatiki ke Anuprayog 27-12-11 8.30-9.00 am PHE-10 Electronic Device 4
Date/Day Time Slot Course Code Video Programme Title January 2012 08-01-12 9.00 9.30 pm PHE-15 Glimpses of the Cosmos 15-01-12 9.00 9.30 pm PHE-02 Simple Harmonic Motion 22-01-12 9.00 9.30 pm PHE-15 Exploring the Night Sky 24-01-12 8.30-9.00 am PHE-02 Dolan February 2012 12-02-12 9.00 9.30 pm PHE-15 On the Trail of Stars 14-02-12 8.30-9.00 am PHE-06 Second Law of Thermodynamics 21-02-12 8.30-9.00 am PHE-02 Coupled Oscillations March 2012 06-03-12 13-03-12 18-03-12 20-03-12 April 2012 08-04-12 15-04-12 May 2012 13-05-12 15-05-12 8.30-9.00 am PHE- 13 Introduction to Crystal Structure 8.30-9.00 am PHE- 15 Astronomical Coordinates 9.00 9.30 pm PHE- 10 Operational Amplifier 8.30-9.00 am PHE- 06 Carnot Cycle 9-00-9.30 pm PHE- 15 Astronomical Measurements (Measurement of Distance and Brightness) 9-00-9.30 pm PHE- 01 Rotating Frames of Reference 9.00-9.30 pm PHE -15 Astronomical Measurements (Measurement of Mass, Temperature and Time) 8.30-9.00 am PHE -10 Logic Gates 5
TENTATIVE SCHEDULE FOR PHYSICS STUDENTS ON DD1 (National Network) JULY 2011 TO MAY 2012 Time: 6.00 AM to 6.30 AM Month/Date* Course Topic July 2011 11-07-11 August 2011 08-08-11 September 2011 12-09-11 October 2011 10-10-11 November 2011 14-11-11 January 2012 09-01-12 February 2012 13-02-12 March 2012 12-03-12 April 2012 09-04-12 PHE-10 PHE-02 PHE-10 PHE-06 PHE-15 PHE-13 PHE-01 PHE-15 PHE-10 Operational Amplifier Coupled Oscillations Transistor Configuration Thermodynamics in Action Exploring the Night Sky Introduction to Crystal Structure Ghurni Nirdesh Tantra (Hindi) The Milky Way Semiconductor Diode May 2012 14-05-12 PHE-15 * Second Monday of every month On the Trail of Stars 6
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 7
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. 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. 8
If not, specify the difficulties: 10. Put a tick mark on the correct response: (i) (ii) (iii) (iv) The level of the course was as I expected. The topics, concepts covered were interesting and informative. The mathematics was as I expected. I would have preferred a nonmathematical explanation. Yes/No, it was too high/ No, it was lower. Yes /No Yes/No, it was Difficult/No, it was easy 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 (iii) If yes, please mention the preferred timings. 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? 9
13. Your overall comments on the course. (Write the comments on the course after studying it.) You may use extra pages. 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? If yes, please list all such TMAs. Yes/No 10
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 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 study the section 1.2 * 1.3 1.4 1.4.1 1.4.2 1.4.3 1.4.4 11
Block 1 Unit 2 : Basic of Positional Astronomy Section 2.2 Explanation of 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 12
Block 1 Unit 3 : Astronomical Techniques Section Explanation of 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 13
Block 1 Unit 4: Physical Principles Section Explanation of 4.2 4.2.1 4.2.2 4.3 4.4 4.4.1 4.4.2 4.4.3 4.4.4 14
Block 2 Unit 5 : The Sun Section 5.2 Explanation of 5.3 5.4 5.4.1 5.4.2 5.5 5.6 5.7 Block 2 Unit 6 : The Solar Family Section 6.2 Explanation of 6.3 6.4 6.5 15
Block 2 Unit 7: Stellar Spectra and Classification Section Explanation of 7.2 7.3 7.3.1 7.3.2 7.4 7.5 Block 2 Unit 8: Stellar Structure Section 8.2 Explanation of 8.3 8.4 8.5 8.6 8.6.1 16
Block 3 Unit 9 : Star Formation Section Explanation of 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 10.2 10.3 10.4 10.4.1 10.4.2 10.5 17
Block 3 Unit 11: Compact Stars Section Explanation of 11.2 11.2.1 11.3 11.3.1 11.4 11.4.1 11.4.2 11.5 11.5.1 18
Block 3 Unit 12: The Milky Way Section Explanation of 12.2 12.3 12.3.1 12.3.2 12.3.3 12.4 12.5 19
Block 4 Unit 13: Galaxies Section Explanation of 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 20
Block 4 Unit 14 : Active Galaxies Section Explanation of 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 21
Block 4 Unit 15: Large Scale Structure and The Expanding Universe Section Explanation of 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 22