Question

The example of non-ohmic resistance is
A) Diode
B) Copper wire
C) Filament lamp
D) Carbon resistor

Answer 1

In this question, we have four devices which are used as resistances. We can identify the ohmic resistance and non-ohmic resistance on the basis of the $VI$graph (straight line) and its slope(constant).

Complete step by step solution: - A non-ohmic resistance is a resistance which does not follow the Ohm’s law. Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
The main Characteristic of Ohmic resistance is the $VI$ curve which is a straight line.
The diode does not have a straight line as a $VI$curve.
The copper wire has a straight line as a $VI$graph.
The filament lamp has a straight line as a $VI$graph.
The carbon resistor has a straight line as a $VI$graph.
So, the diode is a non-ohmic resistance.

Hence, option A is correct.

Additional Information: - The difference between Ohmic and non-ohmic resistances are given below-

S.No.	Ohmic resistance	Non-ohmic resistance
1.	These devices follow the Ohm’s law.	These devices do not follow the Ohm’s law.
2.	For these devices, the $VI$graph is a straight line.	For these devices, the $VI$graph is not a straight line.
3.	For these devices, the slope of the$VI$graph is always constant.	For these devices, the slope of the$VI$graph is not constant.
4.	Example- Copper wire, filament lamp, carbon resistor, etc.	Example- Diode, semiconductors, inductor, etc.

Note: - In this question, we have to keep in mind that if a device follows the Ohm’s law then it is called ohmic resistance and if not then it is called non-ohmic resistance. The main characteristic of an ohmic resistance is that it has a straight line as a $VI$curve and the slope of this straight line is always constant for ohmic resistance. For non-ohmic resistances, opposite characteristics are followed.