AIPMT | 2014Current Electricity and Electrical InstrumentMedium
Question
A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has anemf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance, R, connected across the given cell, has values of
(i) Infinity
(ii) 9.5 Ω,
the ′balancing lengths′, on the potentiometer wire are found to be 3 m and 2.85 m, respectively.
The value of internal resistance of the cell is
(i) Infinity
(ii) 9.5 Ω,
the ′balancing lengths′, on the potentiometer wire are found to be 3 m and 2.85 m, respectively.
The value of internal resistance of the cell is
Options
A.0.25 Ω
B.0.95 Ω
C.0.5 Ω
D.0.75 Ω
R
9.5Ω = 
× 9.5 ΩTopic: Current Electricity and Electrical Instrument·Practice all Current Electricity and Electrical Instrument questions
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