Black Holes

If a dying star's core is less than 1.4 times the mass of the Sun, it becomes ___

• a white dwarf
• a neutron star
• a red giant
• a black hole

If a dying star's core is between 1.4 and 2.8 times the Sun's mass, it becomes ___

• a white dwarf
• a neutron star
• a red giant
• a black hole

If a dying star's core is more than 2.8 times the Sun's mass, it becomes ___

• a white dwarf
• a neutron star
• a black giant
• a black hole

For Earth, the escape velocity is about ___

• 11 km per hour
• 11 km per second
• 600 km per hour
• 600 km per second

A neutron star, with its immense gravity, can have an escape velocity that's up to ___

• one quarter of the speed of light
• half the speed of light
• the speed of light
• twice the speed of light

Nothing can escape, not even light, once the core of a neutron star shrinks down to ___

• roughly 1.8 km
• roughly 8.1 km
• roughly 18 km
• roughly 81 km

The surface around a black hole, where the escape velocity is the speed of light, is called ___

• the observable boundary
• the event horizon
• the progenitor surface
• The Chandrasekhar Limit

To become a black hole,  the original star must have a mass of ___

• more than 1/4 of the Sun's mass
• more than 1.4 times the Sun's mass
• more than 4 times the Sun's mass
• more than 20 times the Sun's mass

If you could turn the Sun into a black hole, then the Earth would ___

• quickly get pulled in
• orbit it slower than it does now
• orbit it pretty much exactly as it does now
• orbit it faster than it does now

The strength of gravity you feel from an object depends on ___

• how large it is and your distance from its center
• how massive it is and your distance from its center
• how large it is and its density
• how massive and dense it is