What are MCB.s? How do they work?

Discuss some appliance of Joule's heating effect. Name few electric heating device & state on what principle do they work.

How is Eddy current produced? How do they flow in a conductor ?

What are the two major components of prokaryotic RNA polymerase? How do they act?

We have ""_(19)^(39)K and ""_(17)^(37)Cl a. What are these nuclides ? " " b. How do they differ?