BALOCHISTAN PUBLIC SERVICE COMMISSION
COMPETITIVE EXAMINATION 2021
FOR RECRUITMENT TO THE POSTS OF
ASSISTANT COMMISSIONER/SECTION OFFICER (B-17)
IN THE SERVICES & GENERAL ADMINISTRATION DEPARTMENT
ASTRONOMY
July 18, 2021
Total Marks 150
Time Allowed 03 Hours
NOTE
i Attempt any five questions All questions carry equal marks
ii All the parts (if any) of each Question must be attempted at one place instead of at different places
iii Candidate must write Q No in the Answer Book in accordance with Q No in the Q Paper
iv No Page/Space be left blank between the answers All the blank pages of Answer Book must be crossed
v Extra attempt of any question or any part of the attempted question will not be considered
Q No 1 a What are spectral lines? How are they produced? Mention situations in which emission and absorption line spectra are produced (15)
b What information can we deduce from Quasar Absorption Lines? (15)
Q No 2 a Discuss the classification of galaxies and how can we see the Milky Way if we are inside it? (20)
b How do galaxies collide in an expanding Universe? (10)
Q No 3 a Define black hole. What would happen if two black holes merged? Will our sun become a black hole? (15)
b How are black holes formed? What are the types of black holes? (15)
Q No 4 a What is the purpose of using telescopes in astronomy? Discuss some major types of it in detail (15)
b What is meant by Hubble Space Telescope? How HST works? Explain briefly (15)
Q No 5 a What is the HII region in astronomy? How can you determine the temperature of HII regions? (10)
b Describe the characteristics of the various kinds of interstellar gas (HII regions, neutral hydrogen clouds, ultra-hot gas clouds and molecular clouds) (20)
Q No 6 a Why do the altitude and azimuth of a star depend on the date, time and location of the observer? How is the altitude of a celestial pole (north or south) related to an observer’s latitude? (Discuss both hemispheres) (15)
b Explain why people living at the equator have 12-hour days throughout the year? Describe possible climate zones of Earth, if the Earth axis is not tilted (15)
Q No 7 a Why do some stars pulsate while some others do not? Consider Cepheids as an example (15)
b Define the terms “thermal equilibrium” and “hydrostatic equilibrium”. How do they apply to stars? (15)
Q No 8 Write short note on any five of the following (30)
i Supernovae
ii Blue Shift
iii Hubble’s Law
iv Luminosity
v Gravitational waves
vi Astronomical Unit (AU)
vii Event Horizon
viii Light Year
ix Proper Motion
x Galactic Halo
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