A conducting medium is shaped in a form of a quarter of an annulus of radii b and a (b a) and thickness t. Specific resistance of the medium is ρ . The correct option(s) is/are :-

Question

A conducting medium is shaped in a form of a quarter of an annulus of radii b and a (b > a) and thickness t. Specific resistance of the medium is ρ . The correct option(s) is/are :-

TestHub · Accepted Answer

Radial flow between the curved faces (shells in series): $R = \int_{a}^{b} \frac{ρ d r}{( π /2 ) r t} = \frac{2 ρ}{π t} ln \frac{b}{a}$ - (A) correct.

Azimuthal flow between the rectangular end faces (shells in parallel): $G = \int_{a}^{b} \frac{t d r}{ρ ( π /2 ) r}$ , giving $R = \frac{π ρ}{2 t l n ( b / a )}$ - (B) correct.

Flow across the thickness gives $R = \frac{4 ρt}{π ( b ^{2} - a ^{2} )}$ , not (C); and (A) differs from (B), so (D) is wrong.

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Options:(select one or more)

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