The relevant magnitude is mainly the black holes' mass. Since black holes are the result of collapsing stars, yes, there are black holes with the mass of a star.
The diameter is usually taken as the diameter of the event horizon. This diameter is directly proportional to the mass; a supermassive black hole such as Sag A* has a diameter comparable to that of a large star.
False. Only the most massive stars will become black holes.
No. They do not have enough mass to become black holes. Depending on the mass they will either become white dwarfs or neutron stars.
False. Medium-sized stars become white dwarfs. Only the most massive stars form black holes.
Except for supemassive black holes, no. Most black holes have about the same mass as a star, but the event horizon is only a few miles across.
Yes. They get sucked into black holes all the time!
All dead big stars do not form black holes because sometimes the collapse of the star is stopped at a smaller size before it becomes a black hole.
Black holes are formed by super massive stars when they collapse. Less massive stars will form neutron stars. Therefore, the original size and mass of the star will determine if a black hole will be created when the star collapses.
The most massive stars become black holes.
No. Black holes are the remnants left behind when the very largest stars die.
They are called "black holes".
Stars can be sucked into black holes.
Yes. When the most massive stars die, their cores collapse to form black holes.