Is it a book or is it something related with Physics?
MCB or mcb may refer to:
Molecular and Cellular Biology, a scientific journal published by the American Society for Microbiology
Monochlorobenzene, an aromatic organic compound
Miniature circuit breaker, a relatively small electrical circuit breaker fitted in consumer units and small distribution boards
Mauritius Commercial Bank, the oldest and largest banking institution in Mauritius
Muslim Co
I took it from net


Mcb means minature cicuit breaker  it just like fuse

The Brainliest Answer!
MCB (miniature circute breaker) A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and interrupt current flow. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city.
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