Electric Current — Prelims Questions

A current of $1.6,\text{A}$ flows through a conductor. If the charge of an electron is $1.6 \times 10^{-19},\text{C}$, how many electrons pass through a cross-section of the conductor in $1,\text{s}$?

A conductor has a number density of free electrons $n = 8 \times 10^{28},\text{m}^{-3}$ and a cross-sectional area $A = 2 \times 10^{-6},\text{m}^2$. If the drift velocity of electrons is $2.5 \times 10^{-4},\text{m/s}$, what is the current flowing through the conductor? (Charge of electron $e = 1.6 \times 10^{-19},\text{C}$)

Which of the following statements about electric current is INCORRECT?

A charge of $300,\text{C}$ passes through a cross-section of a conductor in $5,\text{minutes}$. Calculate the current flowing through the conductor.

A current of $2,\text{A}$ flows through a wire. If the wire has a cross-sectional area of $0.5,\text{mm}^2$, what is the current density in the wire?

If the number density of charge carriers in a conductor is doubled, while keeping the current and cross-sectional area constant, what happens to the drift velocity of the charge carriers?