Question

why the filament of bulb has high melting point

Answer 1

A filament is made up of a substance having high melting point(like tungsten) because a bulb lights up by heating the filament.
The heated filament is the source of light, and if the melting point of filament's substance is low, it may melt.

Answer 2

Answer:

because the filament of bulb is made up of a strong element having high melting point which is called tungsten..

melting point of tungsten is 3380°C