A large electroscope is made with “leaves” that are long wires with negligible mass with tiny spheres at the end. When charged, nearly all the charge resides in the sphere. If the wires each make a angle with the vertical, what total charge must have been applied to the electroscopes.

What is the main difference between electrical and gravitational forces?

A point charge of +Q is placed at the center of a square. When a second point charge of -Q is placed at one of the square’s corners it is observed that an electrostatic force of 4N acts on the positive charge at the square’s center. Now, identical charges of -Q are placed at the other three corners of the square. What is the magnitude of the net electrostatic force acting on the positive charge at the center of the square?

What is the magnitude of force a charge exerts on a charge away?

When the distance of two interacting charges is increased by a factor of 2, the electrical forces between these charges is __________.

Two charges -Q and -3Q are a distance l apart. These two charges are free to move but do not because there is a third(fixed) charge nearby. What must the magnitude of the third charge and its placement be in order for the first two to be in equilibrium.

At each corner of square of side there are point charges of magnitude Q, 2Q, 3Q and 4Q. Determine the magnitude and direction of the force on the charge 3Q.

Particles of charges , , and are placed in a line. The center charge is and is away from each of the others. Calculate the net force on the center charge from the other two.

When the magnitude of two interacting charges is increased by a factor of 2, the electrical forces between these charges is __________.