Why is an incandescent lamp nonlinear?

Answer 1

Because the more you heat up a conductor the more it's electrically resistant. So, when you increase the supply voltage across such a lamp, the current increases as well, but it heats up the filament, which in turn lowers the current.

So, its current depends on 2 variables: voltage and filament temperature.

That's why you find a discrepancy between the resistance you measure with an ohmmeter

and the one you calculate by using its rated power.

Answer 2

An incandescent lamp is nonlinear because its resistance changes with temperature, causing variations in the current flowing through it. This nonlinearity results in its light output not being directly proportional to the input voltage.

Answer 3

because it is a non-ohmic material or something which dos not follows ohms law.thus we get a curve which is linear initially but is curved at the end. hope it helps