In: Physics
1. A black hole is any object satisfying the following condition a) the mass of the object is greater than about 20 solar masses b) the radius of the object is less than its schwarchild radius c) the speed of the object is greater than the speed of light 2. A galactic rotation curve displays a) angle as a function of time b) velocity as a function of angle c) velocity as a function of distance 3. A pulsar believed to be a) A black hole that is acting as a source of x-rays B) a pulsating white dwarf c) a rotating neutron star 4. An important difference between the evolution of a one solar mass star and a more massive star is that the more massive star a) has a degenerate core throughout its lifetime b) does not become degenerate and therefore does not have a helium flash c) skips hydrogen burning and begins with helium burning instead d) lives for a longer time e) alternate between expansion and contraction
1. Any object can be theoretically converted into a black hole if the density of the object is greater than a threshold, this is determined by the schwarzschild radius for the object, so
Option B > the radius of the object is less than its schwarchild radius is the correct answer.
2. A galactic rotation curve displays C) velocity as a function of distance.
3. A pulsar believed to be c) a rotating neutron star.
4. An important difference between the evolution of a one solar mass star and a more massive star is that the more massive star b) does not become degenerate and therefore does not have a helium flash