A metal rod of length 10 cm and a rectangular cross-section of is connected to a battery across opposite faces. The resistance will be
A. maximum when the battery is connected across faces.
B. maximum when the battery is connected across faces.
C. maximum when the battery is connected across faces.
D. same irrespective of the three faces.
The correct answer is the option (a)
Explanation:
Resistance is directly proportional to length and inversely proportional to the cross-sectional area. Resistance will be maximum when l is maximum and A minimum. Both these conditions are met simultaneously when the battery is connected across the faces.