Question

MCB are
A. Miniature circuit breakers
B. Switches
C. Plug
D. Fuse

Answer 1

Hint: Start by writing the definition of MCB. Then move to describing circuit breakers and briefly explain how they operate. Also remember to compare them with fuse and describe why MCBs are preferred over fuse now.

Complete step-by-step answer:
MCB are miniature circuit breakers.
Circuit breakers are electrical switches that are designed to automatically save the electrical circuit from excess current and hence, protect it from short-circuit.
Fuse is an essential safety device, used to save electrical circuits from overcurrent and short circuiting, making it completely useless. Fuse is always made from metal, because they are the best conductors of electric current and are readily available.
Circuit breakers are very similar in function to fuse, except for the fact that unlike fuse, circuit breakers can be reused again and again.
The circuit breaker operates by interrupting the flow of current in the circuit, it can be achieved by multiple methods –
1. It can be done using stored mechanical energy within the breaker, such as a spring or compressed air.
2. High current can also be used to trigger the circuit breaker with things like thermal expansion and magnetic field.
Circuit breakers come in various sizes. MCB (Miniature Circuit Breaker) is also a type of circuit breaker.
Before fuse wires were used in the household and repairing them would be a hassle every time. So MCB are a safe and easy to use safety equipment that are widely used now.
Hence, option A is the correct choice.

Note – Circuit breakers and MCBs are very essential safety equipment that must be installed in every household and factory to ensure there are no incidents due to overload. Failing to install these safety equipment can lead to damaging of costly machines and may result in short-circuit leading to a potentially lethal fire.