Question

Ohm's law can be applied to

• A. ohmic devices
• B. non-ohmic devices
• C. both (a) and (b)
• D. none

Answer 1

The correct option is A ohmic devices

• Ohmic Devices: If a device follows ohm’s law for all voltages across it, the device is called an Ohmic device (In other words, the resistance of the device is independent of the magnitude and polarity of the applied potential difference), and the resistance is said to have a constant value (static resistance). In this case, the plot of V versus I is a straight line passing through the origin.
• Non-ohmic Devices: If a device behaves in a way that is NOT described by Ohm’s law, (i.e. the resistance is not constant, but changes in a way that depends on the voltage across it.) The device is said to be non-Ohmic. In this case V versus I graph is not a straight line, but has some curvy shape. Such devices do not have a constant value of resistance and the resistance is called dynamic resistance because it is constantly changing.