Whats good music to listen to when your studying?is it Mozart and Beethoven and the like?

I have heard of studies that show that certain types of clical can increase concentration and motivation levels, however certain types have been known to be very relaxing such as you would use to fall asleep, what I'm trying to say is that "clical" music is an extremely diverse field, and what works for one person does not work for another, it would be fair to say that due to the usual (but not always) lack of singing, and the unfamiliar musical structure there would be far less distractions for most people, than there would be with pop music, but again it depends on the listener. So my advice would be experiment with music, don't judge music before you've tried it, and find what works for you. I particularly like clical Indian music to work to.