Question

What takes place in the fuse when it melts to break the electric circuit?

• A. Short circuit
• B. Joule heating
• C. Overloading
• D. None of these

Answer 1

The correct option is B

Joule heating

Joule's heating that takes place in the fuse melts the fuse to break the electric circuit and hence prevents accidents.

The material used to make the fuse has a very low melting point and when the current passing through it increases beyond a certain limit, it starts to melt.

Heat produced $H$ = $I^{2}Rt$, where ${}^{\prime }{I}^{\prime }$ is current passing, ${}^{\prime }{R}^{\prime }$ is resistance and ${}^{\prime }{t}^{\prime }$ is time.