Ohm's law our aim is to determine the resistance per centimeter of a given Wire by plotting a graph of potential difference versus current and hence to determine its resistivity to do the experiment we require the following screw gauge battery one-way key riostat voltmeter ammeter measuring scale and resistance wire procedure connect the positive terminal of a battery to the positive terminal of ammeter using a connecting wire connect the negative terminal of your ammeter to the positive terminal of the voltmeter using a connecting wire the negative terminal of the voltmeter is connected to the upper terminal of the rheostat using a piece of wire connect the lower terminal of the rheostat to one end of the one-way key that is the key should be removed using a connecting wire the other free end of the one-way key is connected to the negative terminal of the battery now take a resistance wire stretch it and measure its length using a meter scale and cut the wire at the given point connect it in parallel to the terminals of the voltmeter that is positive to negative the connection is completed now insert the key and Slide the rheostat contact to check the working of the ammeter and voltmeter adjust the sliding contact of the rheostat and note down the value of potential difference V from voltmeter and current I from the ammeter record the reading of the voltmeter and ammeter shift the rheostat contact slowly and record the reading of the voltmeter and ammeter and calculate the value of R in each case shift the rheostat contact slowly similarly take at least 5 sets of independent observations record the readings and plot a graph with the values calculate the resistance per centimeter of The Wire calculate the least count and zero correction of the screw gauge remove the resistance wire from the terminals of the voltmeter the resistance wire is gently gripped between the stud and the screw of the screw gauge note the pitch scale reading and head scale reading calculate the diameter of the wire and hence the radius of the wire calculate the resistivity specific resistance of the material of The Wire resistance per centimeter of the given wire is 0.

066 ohms per centimeter and resistivity of the material of the given wire is 1.01 into 10 raised to minus 6 ohms meter.