Astronomers now think that there is a black hole with more than 4 million times the mass of our Sun at the center of our Galaxy. Roughly how large would the event horizon of such a supermassive black hole be

How do you tell if someone actually cares about you? and just say they do?

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?

Acoil suspended freely, points in some direction when no current is passed through it . can you tell what will happen when a current is passed though it?