Is a light bulb an ohmic conductor?

Answer 1

For a material to be 'ohmic' or 'linear', it must obey Ohm's Law. For Ohm's Law to apply, the ratio of voltage to resistance must be constant for variations in voltage.

An incandescent lamp's filament is manufactured from tungsten, which is 'non-ohmic' or 'non-linear' because the ratio of voltage to current changes for variations in voltage. In fact, MOST conductors and electrical devices (such as diodes) are non-ohmic.

If you were to conduct an experiment that allowed you to record the variation if current flowing through a tungsten filament for variations in voltage, the result would be a curved graph line -in other words, a 'non-linear' (therefore, 'non-ohmic'), graph line.

So, to directly answer your question, NO, a tungsten filament is not an ohmic material.

Answer 2

It depends on the part of the bulb you examine. The glass envelope and vacuum are very good insulators (do not pass a current) and the base is a good conductor as it does not heat up as it transmits the current. The filament (the part that gives off light) has a high resistance to current (is a poor conductor) and heats up as current flows through it. The hot metal is the light source.