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A metal rod of length 10 cm and a rectan...

A metal rod of length 10 cm and a rectangular cross-section of 1 cm `xx (1)/(2)` cm is connected to a battery across oppostie faces. The resistance will be

A

maximum when the battery is connected across 1 cm `xx (1)/(2)` cm faces.

B

maximum when the battery is connected across IO cm `xx 1` cm faces.

C

maximum when the battery is connected across 10 cm `xx (1)/(2)` cm faces.

D

same irrespective of the three faces.

Text Solution

Verified by Experts

maximum when the battery is connected across 1 cm `xx (1)/(2)` cm faces.

resistance of rod, R = `(rho l )/(A)`
`therefore R prop (l)/(A)`
Hence, to obtain large value of resistance its length (l) should be more and cross section area (A) should be less. This is possible when battery is connected both 1 cm `xx (1)/(2)` cm side.
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