Question

Compare the currents in the two segments. That is, is (I_2) greater than, less than, or equal to (I_1)?

a) The surface charge density is larger in wire 1.
b) The number of charges is larger in wire 2.
c) (I_1)
d) (I_2)

Answer 1

In a better conductor, drift velocity is lower because there are more charge carriers available to carry the current, thus each individual carrier moves more slowly to sustain the same current.

Step-by-step explanation:

When comparing two wires of identical cross-sectional areas carrying the same current, the drift velocity will be lower in the better conductor. According to the equation ℓd = I/nqA, drift velocity (ℓd) is the speed at which charge carriers move through the conductor. The term 'I' is the current, 'n' represents the number density of charge carriers, 'q' is the charge of each carrier, and 'A' is the cross-sectional area of the wire. A good conductor has a higher number density of charge carriers, meaning 'n' is larger. For the same current 'I', if 'n' is larger, the drift velocity must be lower because drift velocity is inversely proportional to the charge carrier density. Hence, a better conductor, with more free charges available to carry the current, allows each individual charge to move more slowly while still sustaining the same overall current.