Yes, I used them for my phone and mp3 as well as my laptop. That aren't Super loud, but they were perfect for me when I would be doing homework, cleaning etc.
No, they are smaller speakers, they go based on volume control from whatever source you're using, though they are not the type for blasting if you like that type. I used these as something enough to hear but be able to concentrate on homework. Also used them when I would tan at my friends house.