Question

While overloading, the fuse melts to protect the circuit because of
(1) Joule's law of heating
(2) Ohm's law
(3) Faraday's law
(4) Kepler's law of heating

Answer 1

When large amount of current passes through an electrical circuit, the fuse melts to protect the circuit. In this phenomenon, Joule' Law Of Heating is used. 
When electric current passes through an electrical circuit, the conductor produces a certain amount of heat due to the collision of electrons. According to Joule's Law, this heat is directly proportional to the resistance and the square of the current passed. If there is less or no resistance then a large amount of current passes through an electrical circuit.
A fuse is normally used to protect the circuit from over loading of current and damage. A fuse should have two qualities:
1. It should have high resistance.
2. It should have low melting point.
So, when high amount of current passes through a circuit, it gets heated up due to high resistance and due to the low melting point, the temperature of the fuse wire rapidly increases. Thus, the fuse wire melts down or burns to save the circuit from damage.