"The light is coming from the lamp" is also correct and a literal translation.
Reading other comments in this section, it appears that some Greek speakers use λάμπα to mean a light bulb, although my dictionary gives a different word. This reminds me of another word in this section κουζίνα which is used for oven / stove / cooker as well as kitchen. Very confusing!
Yes, that's true. It's only through context that they can be distinguished. There is also the noun..."φωτιστικό" which is an alternative translation but is not as commonly used.
True but if I had to buy a "light bulb" I'd ask for "μια λάμπα".