Question

why tungsten wire is used in electric bulbs

Answer 1

Because it has high temperature resistance it glow when you pass electricity through it.

Answer 2

Light bulbs glows when electricity is passed through the filament.
The filament must have these following properties 
High melting point     tungsten has melting point of 3422C so it doesn't melt when current is passed it doesn't melt.
Tungsten apart from having high melting point also has high tensile strength. Tensile strength determines how strongly it can be molded into thin wires. Tungsten has low vapor pressure and hence will not produce tungsten vapors when heated. It has low thermal expansion coefficient and hence will not change its shape and structure when heated. This helps the filament not to get separated from the electrodes. Due to all these properties of tungsten, it is used in light bulbs.