Current and Circuits · Paper 1 — Free Physics HL Practice Questions

Two point charges, $+3.0 \times 10^{-6}$ C and $-3.0 \times 10^{-6}$ C, are placed $0.20$ m apart in a vacuum. What is the magnitude of the electric field at the midpoint between the two charges?

A battery of electromotive force $24\text{ V}$ and negligible internal resistance is connected to a resistor of resistance $6.0\ \Omega$. What is the current in the resistor?

A polythene rod is given a net charge of $-3.2 \times 10^{-9}\,\text{C}$ by rubbing it with a cloth. The rod is held close to, but not touching, an initially uncharged small metal sphere suspended on an insulating thread. Which of the following correctly describes the induced charge distribution the sphere and the resulting net electrostatic force on it?

A nichrome heating element has a length of $0.50\text{ m}$ and a cross-sectional area of $2.0 \times 10^{-7}\text{ m}^2$. The resistivity of nichrome is $1.1 \times 10^{-6}\ \Omega\text{m}$. A current of $4.0\text{ A}$ flows through the element. What is the potential difference across the element?