24. Electric Force & Field; Gauss' Law

If a point charge of $Q$ is placed at a distance $r$ above the ground, what is the approximate magnitude of the electric field at a point midway between the charge and the ground (neglecting edge effects and assuming the ground acts as a conducting plane)?

As a proton moves in the direction of the electric field lines, which of the following statements is true about its electric potential energy ($U$)?

If two parallel membranes are separated by a distance of $d$ and a potential difference of $V$ is applied across them, what is the magnitude of the electric field between the membranes?

What is the primary function of the third prong on the plug of an electric appliance?

Two point charges are placed on the x-axis: a charge of $\mathrm{+2}\mu C$ at $x=-0.5m$ and a charge of $-2\mu C$ at $x=\mathrm{+0.5}m$. What is the magnitude of the net electric field at the origin? (Assume $k=8.99\times 109^N{m}^2{C}^{-2}$)

For a point charge $q$ located at the origin, what is the mathematical expression for the electric field at the point $x=0$, $y=0$, $z$ at time $t$ in vacuum?

Four identical point charges are placed at the corners of a square. What is the direction of the net electric field at the center of the square?

In a region of space, the electric field has components $E_y$=$0$ and $E_z$=$0$. Which statement is true about the direction of the electric field in this region?

In the figure, a voltmeter of resistance $R_V$ is connected across points A and B in a circuit containing a battery of emf $E$ and internal resistance $r$, and an external resistor $R$. What is the reading of the voltmeter?

Why are magnetic and electric fields considered force fields?

Two long, parallel wires carry equal currents in opposite directions. At a point exactly midway between the wires, the $E$lectric field is:

Under electrostatic conditions, the electric field just outside the surface of any charged conductor is:

Which of the following best describes how the electric field strength between two point charges varies with the distance between them?

A uniform electric field is directed from left to right between two parallel capacitor plates as shown in Figure 1. Which plate is the positive plate?

What is the primary function of the round third prong in a modern household electric plug?