Which companies are open for all of the branches at IIT BHU, and how many CTCs do they offer?

IIT BHU placements depend a lot on your TPR. Your TPR should have the ability to convince the recruiters and serve you in the most selfless way. He has the power to speak to HR and make you sit for top IT companies provided that you should be talented.

My friend was in the ceramic branch and loved coding. His dream was to get placed in a good IT company. However, very few computer companies approach ceramic students for placements. But because of his exceptional skills, he got recruited to a very good MNC that was IPE only to CS students. 

Ultimately it depends on your TPR and your skills as to what companies approach you with good roles.