VISUAL PHYSICS ONLINE

4.1 ELECTRICITY

P41 0005

You carried out an experiment in which the potential difference between the two ends of a conducting wire varied with respect to the current flowing through the wire. The following measurements were recorded.

V (V) 0 2.0 4.1 5.9 8.0 10.0

I (A) 0 0.1 0.2 0.3 0.4 0.5

a Plot a graph of V versus I [I on x-axis, V on y-axis]

b What is the slope of the graph and what does it represent?

c Use the graph to determine the potential difference across the conducting wire when a current of 0.35 A flows through it.

View solution below only after you have completed the answering the question.

Solution

a

b

The slope of the graph, m is the change in potential difference with change in current or , using rise over run, m = 10 / 0.50 V/A = 20 .

You could choose any two points on the line of best fit, but it makes it easier of they are far apart rather than close together. The slope represents the resistance of the wire. R = 20 .

c

See the plot above. When a current of 0.35 A flows there will be a potential difference of 7.0 V across the wire.