EXPERIMENT – 8

AIM:

To verify the Ohm's law and hence find the value of the unknown resistance.

APPARATUS:

Battery, Ohm's law apparatus which comprises of ammeter, voltmeter, resistance wire, switsh and connecting wires.

PRINCIPLE:

According to the Ohm's law, at a constant temperature, the current flowing through a conductor is directly proportional to the potential difference applied across the ends of the conductor.

FORMULA:

V = IR
Where :
V=Potential difference across the ends of the conductor
I =Current flowing through the conductor
R = Resistance of the conductor

PROCEDURE:

1.Set up the apparatus as shown in the figure.
2.For various positions of the rheostat take the ammeter and voltmeter readings.
3.Take five sets of observations.
4.Take the mean of all the observations.
5.Draw a graph with voltage along the x axis and current along the y axis.

PRECAUTIONS:

1.The connections should be tight.
2.The ends of the wires must be cleaned with sand paper before making the connections.
3.The current should not be allowed to pass through the circuit for a very long time as it heats up the wire and changes its resistance.

RESULT:

1.The graph between current and potential difference is found to be a straight line.
2.The value of the unknown resistance is found to be _________