Question

For small currents, ‘X’ obeys Ohm’s law. But when large currents are passed through the same conductor, it deviates from ohmic behaviour. Identify X.

(a) Metallic conductor

(b) Gallium arsenide

(c) Thyristor

(d) p-n junction diode

The question was asked in an interview.

The origin of the question is Current Electricity in portion Current Electricity of Physics – Class 12

Answer 1

Right answer is (a) Metallic conductor

The explanation is: ‘X’ is a metallic conductor. For small currents, it obeys Ohms’s law and its V-I graph is a straight line. But when large currents are passed through the same conductor, it gets heated up and its resistance increases. It no longer obeys Ohm’s law at higher currents.