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Two cells of emfs approximately 5V and 10V are to be accurately compared using a poteniometer of length 400 cm.A. Toe battery that runs the potentiometer should have voltage of 8 V.B. Toe battery of potentiometer can have a voltage of 15 V and R adjusted so that the potential drop across the wire slightly exceeds 10 V.C. The first portion of 50 cm of wire itself should have a potential drop of 10 VD. Potentiometer is usually used for comparing resistances and not voltages. |
Answer» Correct Answer - B As `R=rho(l)/(A)` resistance is maximum when l is large and A is least. For the give dimensions of wire, resistane will be maximum for l=10cm and `A=1cmxx(1)/(2)cm` |
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