Question

At constant temperature the ratio of potential difference to current is not constant for the following

Answer 1

Answer:

Assuming constant temperature,

Ratio of potential difference to current is the slope of the curve/line formed for a Graph of V vs I.

If the graph represents a line, the ratio of  potential difference to current is constant, the conductor is know to be a ohmic conductor or is know to follow the ohm's law.

In our case,

If the ratio is not constant, then the conductor does not follow the ohm's law or is known to be a non-ohmic conductor.

Examples for such conductors are : a zener diode, LED, transistors, etc.