# Current Electricity: Current density

1. Two wires both carry the same current (I). The moving charged particles in both wires are electrons, but the concentration of moving electrons in wire #1 is double the concentration of moving electrons in wire #2.

Under what circumstances will the drift speed of electrons be the same in both wires? Choose the answer that best fits.

A. if the diameter of wire #2 is 4 times the diameter of wire #1

B. if the diameter of wire #2 is 1/sqrt(2) the diameter of wire #1

C. if the diameter of wire #2 is 1/4 the diameter of wire #1

D. if the diameter of wire #2 is sqrt(2) times the diameter of wire #1

2. Two wires are both made of the same material and both carry the same current (I). The cross-sectional area of wire #1 is double the cross-sectional area of wire #2.

Compared to the electric field in wire #2, the electric field in wire #1 is:

A. 2 times greater

B. 1/2 as great

C. 1/4 as great

D. sqrt(2) as great

E. 1/sqrt(2) as great

F. 4 times as great.

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1. Two wires both carry the same current (I). The moving charged particles in both wires are electrons, but the concentration of moving electrons in wire #1 is double the concentration of moving electrons in wire #2. Under what circumstances will the drift speed of electrons be the same in both wires? Choose the answer that best fits.

A. if the diameter of wire #2 is 4 times the diameter of wire #1

B. if the diameter of wire ...

#### Solution Summary

Questions related to electric current, current density and field are discussed in the solution.