5-1 Electric Fields

Two charges $Q_1$ and $Q_2$ , each equal to 2 nC, are separated by a distance 3 m in a vacuum. What is the electric force on $Q_2$ and the electric field due to $Q_1$ at the position of $Q_2$?

Three point charges of equal magnitude are placed at the vertices of an equilateral triangle. The signs of the charges are shown. Point P is equidistant from the vertices of the triangle. What is the direction of the resultant electric field at P?

An electron enters the region between two charged parallel plates initially moving parallel to the plates. The electromagnetic force acting on the electron ...

The diagram shows two equal and opposite charges that are fixed in place. At which points is the net electric field directed to the right?

A vertical wall carries a uniform positive charge on its surface. This produces a uniform horizontal electric field perpendicular to the wall. A small, positively-charged ball is suspended in equilibrium from the vertical wall by a thread of negligible mass. The charge per unit area on the surface of the wall is σ. It can be shown that the electric field strength E due to the charge on the wall is given by the equation $E=\frac{\sigma}{2\epsilon_o}$ .

What are the units of σ?

A vertical wall carries a uniform positive charge on its surface. This produces a uniform horizontal electric field perpendicular to the wall. A small, positively-charged ball is suspended in equilibrium from the vertical wall by a thread of negligible mass. The charge per unit area on the surface of the wall is σ. It can be shown that the electric field strength E due to the charge on the wall is given by the equation $E=\frac{\sigma}{2\epsilon_o}$ .

The thread makes an angle of 30° with the vertical wall. The ball has a mass of 0.025 kg.

Determine the horizontal force that acts on the ball.

A vertical wall carries a uniform positive charge on its surface. This produces a uniform horizontal electric field perpendicular to the wall. A small, positively-charged ball is suspended in equilibrium from the vertical wall by a thread of negligible mass. The charge per unit area on the surface of the wall is σ. It can be shown that the electric field strength E due to the charge on the wall is given by the equation $E=\frac{\sigma}{2\epsilon_o}$ . The charge on the ball is $1.2\times10^{-6}\ C$ . Determine σ.

-> The value you write is what goes before ___ $\times10^{-6}C\ m^{-2}$

The centre of the ball, still carrying a charge of $1.2\times10^{-6}\ C$

, is now placed 0

.

40 m

 from a point charge Q. The charge on the ball acts as a point charge at the centre of the ball.

P is the point on the line joining the charges where the electric field strength is zero.

The distance PQ is 0

.

22

m

. Calculate the charge on Q. State your answer to an appropriate number of significant figures.

-> The value you enter is what goes before ___ $\times10^{-6}\ C$ $\times10^{-6}C\ m^{-2}$