InterviewSolution
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InterviewSolution
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The emf of the driver cell of a potentiometer is `2 V`, and its internal resistance is negligible. The length of the potentiometer wire is `100 cm`, and resistance is `5 omega`. How much resistance is to be connected in series with the potentiometer wire to have a potential gradient of `0.05 m V cm^(-1)`?A. `1990 Omega`B. `2000 Omega`C. `1995 Omega`D. none of these |
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Answer» Correct Answer - C `k = 0.05 m vcm^(-1) = 5mVcm^(-1)` `I = (kl)/(r ) = (5 xx 10^(-3) xx 1)/(5) = 10^(-3) A` Now, `2 = I(R + r) = 10^(-3) (R + 5)` or `R = 1995 Omega` |
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