Dear Student,
1) In an electric bulb, the filament of the bulb gives light because of the heating effect of electricity.
2) The element of electric iron is made of alloys having a high melting point.
3)An electric fuse is used to protect the electric appliances from high voltage; if any. The electric fuse is made of metal or alloy of metals, such as aluminium, copper, iron, lead, etc. In the case of the flow of higher voltage than specified, fuse wire melts and protects the electric appliances.
Regards