I-V Plots

Question 1

What does an IV plot for a resistor look like? And state your reasons

Answer 1

-Increasing current through a resistor increases its potential difference (PD).
-Doubling the current through a resistor doubles the PD.
-Current through a resistor is directly proportional to PD at constant temperature, defining it as an ohmic conductor obeying Ohm’s law.
-A steeper line on a graph indicates smaller resistance for an ohmic conductor.

Question 2

What does an IV plot look like for a Filament Bulb? And state your reasons

Answer 2

-Current isn’t directly proportional to potential difference, so it’s not an ohmic conductor (doesn’t obey Ohm’s law).
-Increasing current through the bulb raises filament temperature, increasing its resistance.
-Filament resistance is lowest with high current, showing as the steepest gradient on the current-PD graph.

Question 3

What does an IV plot look like for a Diode? And state your reasons

Answer 3

-A diode conducts current in one direction, known as its forward direction.
-Above 0.6V in the forward direction, current rapidly increases due to a dramatic decrease in resistance.
-In the reverse direction, the diode’s resistance remains high, blocking current flow.