A circular portion is cut out of a disc of thickness t, its resistivity is P and radii of disc are a and b (b > a). A potential difference is maintained between outer and inner cylindrical surfaces of the disc. What is resistance of the disc ?

Engineering

Physics

Ohm Law and Current Basics

Question

$2 πPt (\frac{1}{a^{2}} - \frac{1}{b^{2}})$

$\frac{P}{2 πt} (\frac{b^{2} - a^{2}}{ab})$

$P (\frac{1}{a} - \frac{1}{b})$

$\frac{P}{2 πt} \ln (\frac{b}{a})$

LiveFree JEE Main Previous Year Online Papers Live Free JEE Advance Previous Year Online Papers

College PredictorLive

Know your College Admission Chances Based on your Rank/Percentile, Category and Home State.

Get your JEE Main Personalised Report with Top Predicted Colleges in JoSA

$dR = ρ \frac{l}{A} = ρ \frac{dx}{(2 πx) t}$
$R = \frac{P}{2 πt} \int_{a}^{b} \frac{dx}{x} = \frac{P}{2 πt} \ln \frac{b}{a}$

Please subscribe our Youtube channel to unlock this solution.