Electrostatics

Which of the following statements is true regarding the interaction between electric charges?

A neutral metal sphere is charged by bringing a positively charged rod near it and then momentarily grounding the sphere. What is the final charge on the sphere?

Two point charges, $q_1$ and $q_2$, are separated by a distance $r$. If the magnitude of the charges are $q_1 = 3 \times 10^{-6} C$ and $q_2 = 5 \times 10^{-6} C$, and the separation distance is $r = 0.5 m$, what is the magnitude of the electrostatic force between them? (Assume $k = 9 \times 10^9 N m^2/C^2$)

Three identical charges $q$ are placed at the vertices of an equilateral triangle with sides of length $a$. What is the magnitude of the net force on one of the charges?

A positively charged rod is used to charge a neutral metallic sphere by induction. Subsequently, a negative charge is brought near the sphere. What will happen?

A sphere with a charge of +8e is brought into contact with an identical sphere with a charge of -4e. After the spheres touch and are then separated, what is the charge on each sphere?

Three charges are arranged in a line. Charge $q_1 = +2 \mu C$ is at $x = 0 m$, charge $q_2 = -3 \mu C$ is at $x = 0.2 m$, and charge $q_3 = +4 \mu C$ is at $x = 0.4 m$. What is the net force on charge $q_1$?

Which of the following materials is best classified as a conductor?

A neutral electroscope is charged through induction using a positively charged rod. Then the electroscope is grounded. What is the charge of the electroscope after the positively charged rod is removed?

A charged particle with charge +q and mass m is placed in an electric field created by two other fixed charges. What is the acceleration of the particle at the instant it is released, if the net electrostatic force on it is F?