Graphs of current against potential difference (or vice versa) are useful for two reasons. The first is that Ohm's law can be confirmed or declined for a given conductor (depending on whether current and voltage are proportional). The second is that the resistance of a conductor at a given point is the ratio of V/I. Note that this is not the same as the gradient of a V vs I graph.
Use quizzes to practise application of theory.
START QUIZ!
The graph represents the current against voltage for a conductor.
The resistance of the conductor is
R is 1/gradient
The gaph represents the current against voltage for a conductor:
The change in resistance from 2 V to 4 V is
Resistance is the ratio of V/I. This is 2 Ω at 2 V and 1 Ω at 4 V.
The resistance of a thermistor gets less when it gets hot.
Which graph represents the IV characteristics of a thermistor?
R is V/I so gradient gets steeper if resistance increases.
The reason V is plotted on the x axis is:
V is varied and I is measured so V is the independent variable, this is usually plotted on the x axis.
In an experiment to measure V and I for a resistor the following graph was obtained:
As you can see the line does not pass through the origin. The reason for this could be:
How much of IV graphs have you understood?
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