Drift Velocity — Prelims Questions

A copper wire of cross-sectional area $1.0 \times 10^{-6},\text{m}^2$ carries a current of $2.0\,\text{A}$. If the number density of free electrons in copper is $8.5 \times 10^{28},\text{m}^{-3}$, what is the drift velocity of the electrons? (Charge of electron $e = 1.6 \times 10^{-19},\text{C}$)

Which of the following statements is TRUE regarding the drift velocity of electrons in a metallic conductor?

A current of $1.6\,\text{A}$ flows through a conductor. If the number of free electrons per unit volume is $10^{29},\text{m}^{-3}$ and the cross-sectional area of the conductor is $1.0 \times 10^{-5},\text{m}^2$, what is the drift velocity of the electrons? (Charge of electron $e = 1.6 \times 10^{-19},\text{C}$)

If the electric field across a conductor is doubled, what happens to the drift velocity of the electrons, assuming all other factors remain constant?

Two wires, A and B, are made of the same material and have the same length. Wire A has a radius $r$, and wire B has a radius $2r$. If the same current flows through both wires, what is the ratio of the drift velocity in wire A to that in wire B ($v_{dA} : v_{dB}$)?

Which of the following factors does NOT directly affect the drift velocity of electrons in a conductor for a given electric field?