Question

You are given three pieces of wire that have different shapes (dimensions). You connect each piece of wire separately to a battery. The first piece has a length L and cross-sectional area A. The second is twice as long as the first, but has the same thickness. The third is the same length as the first, but has twice the cross-sectional area. Rank the wires in order of which carries the most current (has the lowest resistance) when connected to batteries with the same voltage difference.

A. Most Current
B. Wire of length L and area 2A
C. Wire of length L and area A
D. Wire of length 2L and area A
E. Least Curren

Answer 1

Step-by-step explanation:

Resistance of first wire

R₁ = ρL / A where ρ is specific resistance

for second wire the resistance

R₂ = ρ2L / A = 2 ρL / A

For third wire

R₃ = ρL /2 A

The resistance is in the order

R₂ > R₁ > R₃

So , current will be maximum in R₃

I₃ > I₁ > I₂

Where I₁ , I₂ and I₃ is current in first , second and third wire .