Fall 2000 ASTR 1120-001 Quiz 4

Choose the single best answer and enter it on your scantron form. Be sure to fill in your name and student number.

  1. A fundamental postulate of special relativity is:
    (a) there exists an absolute time, the same for all observers; (b) objects in a gravitational field fall at the same rate; (c) light is both a particle and a wave; (d) light diminishes as the inverse square of distance; (e) the speed of light is the same for all observers.

  2. Which of the following is not a consequence of Einstein's theory of special relativity:
    (a) the uncertainty principle; (b) E = m c2; (c) the speed of light is an absolute speed limit; (d) time dilation; (e) Lorentz contraction?

  3. A friend in a racecar passes you at almost the speed of light. Relative to you, the light from the racecar's headlamps:
    (a) moves hardly at all; (b) moves at almost the speed of light; (c) moves at the speed of light; (d) moves almost twice the speed of light; (e) moves almost four times the speed of light.

  4. You are not normally aware of special relativistic effects because:
    (a) you cannot see light; (b) you are not near a black hole; (c) you move at much less than the speed of light; (d) of quantum mechanical effects; (e) special relativity involves advanced mathematics.

  5. If you traveled through the Galaxy at near the speed of light, the Galaxy would appear:
    (a) normal, but moving by fast; (b) relativistically beamed ahead of you; (c) relativistically beamed behind you; (d) concentrated in a thin ring perpendicular to the direction you are moving; (e) invisible.

  6. The superluminal (faster-than-light) motion observed in some cosmic jets indicates that:
    (a) special relativity is wrong; (b) the jet is moving faster than the speed of light; (c) the jet is moving towards us at almost the speed of light; (d) the jet is moving away from us at almost the speed of light; (e) the jet is falling into a black hole.

  7. You watch a friend fall through the horizon of a 30 solar mass black hole. Which of the following is false? The friend appears:
    (a) extremely redshifted at the horizon; (b) to freeze to a halt at the horizon; (c) to fall all the way to the central singularity; (d) stretched by tidal forces; (e) dead.

  8. At the instant you pass through the horizon of a 108 solar mass black hole, you observe that:
    (a) time has come to a halt (your watch has stopped); (b) all the future of the Universe passes before your eyes; (c) the Universe appears concentrated into an ever-diminishing patch of sky, which closes off entirely at the instant you pass inside, leaving you in blackness; (d) you are roasted by the Hawking radiation; (e) nothing special happened at the horizon.

  9. The x-ray binary Cyg X-1 contains an optically-observed massive blue main sequence primary in orbit with a compact companion. Astronomers believe that the compact companion is a black hole because:
    (a) it is ripping the primary to pieces; (b) its mass exceeds the maximum mass of a neutron star; (c) the Hubble Space Telescope reveals a black object at the center of the accretion disk; (d) the primary appears highly distorted; (e) the x-rays are so energetic.

  10. Which of the following statements about wormholes is false:
    (a) wormholes connecting different Universes exist as mathematical solutions of general relativity; (b) the collapse of a star to a black hole produces a wormhole; (c) if a wormhole formed, it would be unstable and would fly apart rapidly; (d) a traveler could not pass through a wormhole; (e) to stabilize a wormhole would require negative mass at its throat.