problem 1:

a) Express the distances of the stars Sirius B and Antares from the Earth in light years.

b) Compare the brightness of the stars Sirius B and Sirius A.

c) The zenith distance of a star at latitude 30° N is 25°. Compute its declination.

d) The local time at Chennai is 8 p.m. compute the local time at New Delhi at that time.

e) Compute the magnitude of the faintest object that a 1 m telescope can detect.

problem 2:

a) Describe why the temperature of sunspots is lower than their surroundings. What do you mean by the term butterfly diagram?

b) Describe the three phases of the formation of planets from the solar nebula.

c) Describe the atomic origin of emission and absorption spectra.

d) prepare down the order of magnitude through which the internal temperature of the Sun is higher than its surface temperature.

Describe the energy generation process at the core of a star.

e) Show that for a polytrop,

P = P_c θⁿ⁺¹
Where P_c is central pressure and n is polytrophic index.

problem 3:

a) Describe 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.

b) What do you mean by the term cosmic abundance? How does it relate to the solar system abundance? How do you distinguish between population I and population II stars?

c) What do you mean by the term planetary nebula? Describe the concept of Chandrasekhar limit.

d) The mass and radius of a neutron star is 2M_Θ and 15 km, correspondingly. Compute the value of gravitational red shift for light of wavelength 6000 Å at a distance of 2 m from its surface.

e) Describe the difference between rigid body rotation and Keplerian motion. What do you mean by galactic longitude?

problem 4:

a) Describe Hubble’s scheme of galaxy classification. Why has this scheme proved lasting? What class has been assigned to the Milky Way Galaxy?

b) With the help of a diagram, describe the unified scheme for understanding active galactic nuclei.

c) Describe how Cepheid variables can be employed to measure the astronomical distances.