Question

what happens if we use a fuse made of same wire which is used to make the electric circuit

Answer 1

Fuse is a safety device used to prevent elctrical appliances from overloading in electrical circuits.
Generally fuse wire is made up of tin and lead alloy and have high resistance and low melting point.
when excess current flows, fuse wire melts and electrical circuit breaks thus prevents from overloading.
if copper wire is used as fuse then as it has high melting point , when excess current flows in circuit then fuse wire may not melt thus all the electrical appliances gets damaged.

Answer 2

Fuse wire  is made up of tin and the electric circuit is made up of copper so if the fuse is made up of copper, so when there will be excess current flow the wire will first of all melt and it will result in damaging all the appliances connected to it at that time.