Question

What is MCB in household circuit connection?
A) Micro Circuit Breakers
B) Miniature Circuit Breakers
C) Miniature Circuit Builders
D) Mega Circuit Blockers

Answer 1

Hint: MCBs are small electromagnetic devices that serve the purpose of breaking a circuit.

Complete step by step answer:
The full form of MCB in household circuit connections are Miniature Circuit Breakers. They are small electromagnetic devices used as a protective measure in electrical circuits.
So the correct answer is B) Miniature Circuit Breakers.

When current exceeds in a circuit, either due to overloading by connecting many appliances at the same time or due to a short circuit, they break off the circuit, thus preventing overheating and fires. They can also be toggled physically, similar to a conventional switch.
Additional information:

Working:- MCBs work on the principle that a current carrying wire produces a magnetic field around it.
They consist of a molded insulated casing and house a coil, a bimetal strip, a spring and electrical contacts. The electrical contacts connect the circuit and are held in place by the resistive forces of the spring.
Whenever a current higher than its rating passes through the MCB, the coil produces a high magnetic field which has an effect on the bimetal strip. (A bimetal strip is just a strip where two smaller strips made of different metals are pasted together in equal or unequal sizes).
The bimetal strip overcomes the resistive forces of the spring. This in turn trips the latch of the MCB, thus effectively switching off the circuit.

Note: The student can remember the full form of MCB by recalling its purpose. For remembering the purpose he/she can keep in mind how sometimes their kitchen’s electric power goes with a loud noise from the circuit board when their mother tries to switch too many appliances on at the same time.