Class Test II

total marks - 10, time - 30 minutes

The Test

1. Explain, why smaller planets, natural satellites, asteroids etc. are rocky whereas the bigger planets are all gaseous. [4]
2. Sun has an average magnetic field of a few Gauss. If the magnetic flus is preserved, what would the field strength be in its white dwarf stage? [4]
3. A bunch of neutrinos were detected by Kamiokande from the supernova 1987A. Why/how are the neutrinos produced in a supernova? [2]

The Supplementary Test

1. What is a main sequence star? [1]
2. How can a black hole be observed? [1.5]
3. A 4 $\mbox{{\rm M}$_{\odot}$}$ star nears its final stages and ejects a shell of gas in the form of a planetary nebula, while the core collapses into a white dwarf. What is the minimum possible mass of the planetary nebula? [1.5]
4. How is energy transported from the centre of a 1 $\mbox{{\rm M}$_{\odot}$}$ star? [1.5]
5. What is the most important factor in determining the evolutionary history of a star? [1.5]
6. What is the mass-radius relation of a degenerate star (white dwarf, neutron star)? [1.5]
7. Under which condition would a star, inspite of having a particular mass, follow a very different evolutionary path. [1.5]