Question

A metal rod of length $10cm$ and a rectangular cross - section of $1cm\times \frac{1}{2}cm$ is connected to a battery across opposite faces. The resistance will be

• A. maximum when the battery is connected across $1cm\times \frac{1}{2}$ cm faces
• B. maximum when the battery is connected across $10cm\times \frac{1}{2}cm$ faces
• C. maximum when the battery is connected across $10cm\times$ 1 cm faces
• D. same irrespective of the three faces

Answer 1

Answer: (A)

Resistance is inversely proportional to area.
Hence resistance will be maximum when the battery is connected across $1cm\times$ $(1/2)cm$ faces.