Question

What would be the resistivity of a perfect conductor in ohm-meters?

0
1
100
Infinity

A current of 3.50 A flows through the leads of an electric appliance. How long does it take for 6.50 C of charge to pass through the leads?
1.8 s
22.8 s
0.5 s
10 s

Answer 1

The resistance of a perfect conductor is 0 Ohm, so the resistivity is necessarily also 0 (Ohm.meter). Resistivity = Resistance * (length)/(cross-section area).

Use the current-charge-time formula:

Current = (amount of charge) / (time) = 6.5C / t = 3.5A

so t=6.5C/3.5A = 1.86 seconds

The closest answer choice is 1.8s (but it really should have been 1.9s)