Question

Question for Lab Written Exam

Slide wire potentiometer: electric field in the wire and how to calculate potential difference along the wire

Answer 1

A battery of emf E is connected the end terminal A and B of potentiometer with rheostat R_h, resistance box and key K in series.

The ends of the R₁ are connected to terminal A and jockey J through galvanometer. The resistance R₁ is connected to cell E₁and key K₁ in series.

Close key K and adjust the resistance from resistance box so that the potential across the potentiometer wire is grated then which is to be measured. Close key K₁. The current flows through R₁. A potential difference is developed across R₁. Adjust the position of jockey on potentiometer wire such that galvanometer shows no deflection. Let this position is J. Let AJ length is l of potentiometer wire. Galvanometer shows no deflection because potential difference is same if K is the potential gradient of potentiometer wire, then potential difference across R₁ that is