Possibly useful formula: tex2html_wrap_inline115 or tex2html_wrap_inline117

Where L=angular momentum, M=mass, R= radius, tex2html_wrap_inline125 spin rate

  1. For a tex2html_wrap_inline127 star, core-collapse models for SNII predict that a ``neutron'' star will be left behind at the center of the SNII remnant. Which of the following properties are predicted for the neutron star?

    ___ Rapid rotation

    ___ Large abundances of S- and R-process elements

    ___ Mass less than tex2html_wrap_inline129

    ___ Strong magnetic field

  2. If the Sun expanded to 4 times its current radius

    (a) would it spin faster, slower or the same as it does now (1/30 revolution per day)?

    (b) By what factor?

  3. What is the best explanation for a pulsar?

    ___ Rapidly spinning Black Hole with a large magnetic field

    ___ Rapidly spinning neutron star that has collapsed to within it's event horizon

    ___ Rapidly spinning neutron star with a strong magnetic field aligned with along its spin axis

    ___ None of these is correct

  4. Suppose we observe a SNII remnant and do not find a pulsar. Which of the following are possible explanations for this non-detection?

    ___ The beamed radiation of the pulsar is oriented such that it does not reach the earth

    ___ Instead of forming a neutron star, the core collapse resulted in a black hole

    ___ The star that exploded was not massive enough to form a neutron core

    ___ None of the above are correct

  5. If the Earth could be compressed to a small enough radius, it would become a black hole, True or False?

  6. Which of the following are predictions of Special Relativity?

    ___ The clock in a spaceship traveling at a high velocity with respect to the Earth will run more slowly than a clock on Earth

    ___ If you perform an experiment to measure the speed of light, you will always get the same answer independent of your velocity

    ___ Neutron stars will be observable as pulsars

    ___ Clocks near black holes will run backwards

  7. To the best of our current knowledge, if a neutron star exceeds tex2html_wrap_inline131 then the gravitational forces overcome neutron degeneracy forces and the neutron star begins to collapse. What stops the collapse?

  8. The equation for escape velocity is tex2html_wrap_inline133 where G is a constant, M is the mass of the object from which escape is to be attempted and R is the radius from which the escape will be made. Given this equation

    (a) Compare the escape velocities from the surface of the Earth for a hydrogen atom (with a mass of tex2html_wrap_inline141 grams) and the Space Shuttle (with a mass of tex2html_wrap_inline143 grams). Think about this carefully - it is right on the edge of being a trick question.

    (b) Use a little algebra to manipulate the equation to solve for radius in terms of the other variables.

  9. What is an event horizon?

    ___ The outer surface of the collapsed core of a massive star

    ___ the extent of the gravitational pull from a black hole

    ___ the boundary near a singularity inside of which the escape velocity exceeds the speed of light

    ___ all of the above are correct

Michael Bolte
Mon Mar 9 22:39:50 PST 1998