AIM: To verify the ohm’s law and hence determine the unknown resistance of the given material of the wire.
APPARATUS: A battery, an ammeter, voltmeter, rheostat, plug key, coil of unknown substance, connecting wire, etc...

CIRCUIT DIAGRAM:

PROCEDURE:
1. The circuit is connected as per the circuit diagram.
2. The plug key is inserted and the rheostat is adjusted so that a definite amount of current (I) flows in the circuit. This value of current is recorded.
3. As the current flows through the unknown resistance a potential difference is developed which is read from voltmeter (V).
4. The procedure is again adjusted to a different value of current (I) and the corresponding (V) values are noted down.
5. The procedure is repeated for at least 5-6 current readings and for voltage also.
6. A tabular column is drawn and the readings of I and V are tabulated.
7. Graph of V Vs I is down. A straight line is obtained.
8. The slope of the graph is found out. The slope gives the resistance (R) of the unknown
resistance.

OBSERVATIONS:
1. Range of Voltmeter =_____________ V
2. Range of Ammeter =______________ A
3. Least count of voltmeter (1Div)= ____________ V
4. Least count of ammeter (1Div)= ____________ A
5. E.M.F of the Battery = _____________V

OBSERVATION TABLE:

GRAPH: Obtain value of `R` via slope of `V` vs `I `= ___________  $$\Omega $$.

RESULT:
Unknown Resistance `R `
a) By calculation ________$$\Omega $$.
b) By Graph ________$$\Omega $$.