Activity: To Study the Variation of Potential Drop Along a Uniform Wire Using a Potentiometer Aim To study the variation of potential drop with length of a uniform wire and hence verify the principle of a potentiometer. Apparatus Required Potentiometer, driver cell (battery), rheostat, galvanometer, jockey, given cell, key, voltmeter (optional), connecting wires. Principle A potentiometer works on the principle that the potential drop across a uniform wire carrying steady current is directly proportional to its length . Mathematically: V ∝ l or V = k l where: V = potential drop l = length of wire k = potential gradient (potential drop per unit length) Theory When a steady current flows through a uniform potentiometer wire, the potential drop along the wire is uniform. Using the null deflection method, the potential difference across a cell can be measured accurately without drawing any current from it. This ensures high accuracy. The principle is verified by showing that the rati...
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