Question

The following table shows current in Amperes and potential difference in Volts.

V (Volts)	I (Amp)
4	9
5	11.25
6	13.5

(i) Find the average resistance.

(ii) What will be the nature of the graph between the current and potential difference? (Do not draw a graph.)

(iii) Which law will the graph prove? Explain the law.

 

Answer 1

(i). From Ohm's law, we have
R=V/I

V (volts)	I    (amp)	R (ohm)
4	9	4/9=0.44
5	11.25	5/11.25=0.44
6	13.5	6/13.5=0.44

Therefore, average resistance = (0.44+0.44+0.44)/3 =0.44 Ω 

(ii)  The nature of the graph between the current and potential difference will be a straight line passing through origin (0,0).

(iii) The graph proves Ohm's law. Ohm's law states that, under constant temperature and physical conditions, the current flowing through a conductor is always proportional to the potential difference across it i.e. V∝I or, V = RI