Question

You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the smallest possible resistance, you should attach the leads to the opposite faces that measure.
A) 3 cm × 5 cm.

B) 3 cm × 8 cm.

C) 5 cm × 8 cm.

D) Any pair of faces produces the same resistance.

Answer 1

Answer:

$c. 5cm \times 8cm$

Explanation:

The dimensions $5cm\times 8cm$ have the highest cross-sectional area combination of $40cm^2$.

-Resistance reduces with an increase in cross sectional area.

-$Reason-$Electrons have alarger area to flow through.