Question

Explain what a quasar is and how it is different from a "regular star"

Answer 1

When material falls into the accretion disc around a supermassive black hole it gets heated by friction and gravitational effects to the point where it emits huge amounts of energy. This is a Quasar.

The main stream stars have much lower luminousity than Quasars. Quasars are radio sources, which will have the highest luminousity in stellar objects, whereas the luminousity offered majority of stars is due to nuclear fusion. Since Quasars are extremely luminous they are visible even from earth