Physics
Assertion (A) : MCB is more effective than a fuse in household wiring.
Reason (R) : MCB can be reset (raised up) after tripping whereas fuse must be neglected once blown.
- Both A and R are true and R is the correct explanation of A
- Both A and R are true and R is not the correct explanation of A
- Assertion is true but reason is false
- Assertion is false but reason is true
Static Electricity
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Answer
Both A and R are true and R is the correct explanation of A
Explanation
An MCB responds very quickly (in a few-tens of milliseconds) to over-current or short-circuit conditions, automatically opening the circuit and preventing damage. Once the fault is cleared the same device can be reset by simply flipping its switch, so it is reusable and convenient.
A fuse, on the other hand, melts when excessive current flows; it then has to be replaced with a new one. Because of this ease of resetting (together with its rapid, reliable action), an MCB is considered more effective than a fuse.
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