Q20 of 31 Page 19

While doing an experiment with potentiometer (Fig 3.5) it was found that the deflection is one sided and (i) the deflection decreased while moving from one end A of the wire to the end B; (ii) the deflection increased. While the jockey was moved towards the end B.


(i) Which terminal +or –ve of the cell E1, is connected at X in case (i) and how is E1 related to E?


(ii) Which terminal of the cell E1 is connected at X in case (ii)?


(i) In case (i), the deflection decreases, magnitude of current in the wire decreases and potential difference across A and jockey decreases. The deflection is one sided. This is only possible if positive terminal of E1 is connected at X and E1>E.


(ii) In case (i), the deflection increases, magnitude of current in the wire increases and potential difference across A and jockey increases. This implies, negative terminal of E1 is connected at X.


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