Why bulbs are not used in place of resistors to prove ohm's law?

Asked by  | 4th Oct, 2013, 09:16: AM

Expert Answer:

A bulb is a non-ohmic resistor. This means that, the resistance of the bulb changes with temperature.
 
For Ohm's law to be obeyed V/I = R. Thus, resistance needs to be constant even when I and V change.
Now, if we replace the resistor with a bulb, when current changes, temperature of the filament of bulb also changes. This changes the resistance of the bulb.
 
Thus, bulbs cannot be used to prove Ohm's law.

Answered by Romal Bhansali | 4th Oct, 2013, 07:26: PM

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