Miniature circuit breaker (MCB) works on the heating effect of current.
Correct option is A. True
MCB works on the heating effect of the current.
Whenever continuous over-current flows through MCB, the bimetallic strip is heated and deflects by bending. As this mechanical latch is attached with the operating mechanism, it causes to open the miniature circuit breaker contacts, and the MCB turns off thereby stopping the current to flow in the circuit.