A potentiometer wire of length 100 cm has a resistance of 10 ohm
PHYSICS · Single correct · CBSE · Physics · Current Electricity · Current Electricity
Problem
A potentiometer wire of length 100 cm has a resistance of 10 ohm. It is connected in series with a resistance and an accumulator of emf 2 V and of negligible internal resistance. A source of emf of 10 mV is balanced against a length of 40 cm of the potentiometer wire. What is the value of external resistance?
(a) 890 Ω
(b) 600 Ω
(c) 650 Ω
(d) 790 Ω