Question

Why does the resistance become vey low when short circuit occurs by the contact of a live wire with a neutal wire.

Answer 1

During short circuit there is a surge, i.e., large flow of current through the conductor ,i.e., the wire. Now, from ohm's law

V= IR

or, R = V/I,

so as the current increases the resistance drops.

Physically, resistance is nothing but the opposition offered to the flow of the current thorough any material and during short circuit as the flow of the current increases, which is possible only if the opposition offered by the material is now reduced ,i.e., only if the resistance is reduced.