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In a potentiometer experiment for measur...

In a potentiometer experiment for measuring the emf of a cell the null point is at 240 cm when we have a `400 omega` resistor in series with the cell and galvanometer. If the series resistance is reduced to half, the null point will be at

A

120 cm

B

240 cm

C

480 cm

D

600 cm

Text Solution

Verified by Experts

The correct Answer is:
B
At null point no current flows thorught galavanometer. Therefore , the resistance connected in series with galvanomter at null point positive will be ineffective . Thus , null point is obtained on potentiometer wire at the original position after removal of series resistance from the galvanometer.
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