what is the mass of light ?
Personally, I don't think black holes make any light in the first place, so it would be a moot point (if I'm right.) Light is an electromagnetic phenomenon. I don't believe there are any electromagnetic interactions going on inside a black hole, so no light is even trying to get out.
The light can't escape because the speed of light isn't fast enough to reach the escape velocity of a black hole at its event horizon. Its like throwing a ball into the air - it can't escape earth's gravity because it isn't moving fast enough. At the event horizon of a black hole, the escape velocity becomes equal to the speed of light, so even light doesn't move fast enough to escape if its a tiny bit closer than the horizon.
Although the above answers sound good, they are in fact partially wrong, and you are right. They are overlooking the most well known concept that Einstein came up with: E= mc^2 (E = energy, m = mass, c = speed of light). When we are dealing with black holes, there is no need to differentiate between mass and energy - they are equivalent. So, it it just as valid to say that light is mass or that matter is energy. However, the above answers are good in the sense that it is easier to think of light as an energy wave to answer your question. If you want to know that mass of your light, just divide the energy of it my c^2.
Photons do not have mass, but they do have energy. Energy couples gravitationally in the general theory of relativity, thus allowing gravity to affect light. Most people know speed affects time, especially speeds that are a a significant fraction of light speed Related to this, and also covered in the theory, is that gravity affects time, REALLY! So now you must be asking does time have mass? As a character in the game HALO says, Hee Hee Hee! But seriously real good question!! Hope this answer was informative and a little bit humorous. Also if you have a planetarium near you, visit it. I'm a member of The American Museum of Natural History in NY City;
Your assumption is invalid. Light travels the gravitational geodesic, that is, it is bent by the local gravity field by an amount proportional to the strength of that field. This does not require light to have a mass, and it has none. Light moves away from a gravitational mass at its usual speed (c=186,282.3979...miles per second). In strong fields its path is bent. In a strong enough field the path is bent into a loop, so light goes out a ways, and comes right back. This is a black hole.
