Three identical metal balls A, B, and C are mounted on insulating rods. Ball A has a charge +q and balls B and C are initially uncharged (g is the usual symbol for electric charge). Ball 4 is touched first to ball B and then separately to ball C. At the end of this experiment, the charge on ball A is A. +g/2. B. +g/3. C. +g/4. D. none of the answers

Earth has a net charge that produces an electric field of approximately 150 N/C downward at its surface. (a) What is the magnitude and sign of the excess charge, noting the electric field of a conducting sphere is equivalent to a point charge at its center? (b) What acceleration will the field produce on a free electron near Earth’s surface? (c) What mass object with a single extra electron will have its weight supported by this field?

(i) A metallic sphere A of radius 1.00 cm is several centimeters away from a metallic spherical shell B of radius 2.00 cm. Charge 450 nC is placed on A, with no charge on B or anywhere nearby. Next, the two objects are joined by a long, thin, metallic wire (as shown in Fig. 25.19), and finally the wire is removed. How is the charge shared between A and B? (a) 0 on A. 450 nC on B (b) 90.0 nC on A and 360 nC on B, with equal surface charge densities (c) 150 nC on A and 300 nC on B (d) 225 nC on A and 225 nC on B (e) 450 nC on A and 0 on B (ii) A metallic sphere A of radius 1 cm with charge 450 nC hangs on an insulating thread inside an uncharged thin metallic spherical shell B of radius 2 cm. Next, A is made temporarily to touch the inner surface of B. How is the charge then shared between them? Choose from the same possibilities. Arnold Arons, the only physics teacher yet to have his picture on the cover ol Time magazine, suggested the idea for this question.

A sphere has a net charge of 8.05 nC, and a negatively charged rod has a charge of 6.03 nC. The sphere and rod undergo a process such that 5.00 109 electrons are transferred from the rod to the sphere. What are the charges of the sphere and the rod after this process?

Unreasonable results A wrecking yard inventor wants to pick up cars by charging a 0.400 m diameter ball and inducing an equal and opposite charge on the car. If a car has a 1000 kg mass and the ball is to be able to lift it from a distance of 1.00 m: (a) What minimum charge must be used? (b) What is the electric field near the surface of the ball? (c) Why are these results unreasonable? (d) Which premise or assumption is responsible?

The fundamental charge is e = 1.60 1019 C. Identify whether each of the following statements is true or false. (a) Its possible to transfer electric charge to an object so that its net electric charge is 7.5 times the fundamental electric charge, e. (b) All protons have a charge of +e. (c) Electrons in a conductor have a charge of e while electrons in an insulator have no charge.

An amoeba has 1.001016protons and a net charge of 0.300 pC. (a) How many fewer electrons are there than protons? (b) If you paired them up, what fraction of the protons would have no electrons?

There are very large numbers of charged particles in most objects. Why, then, don't most objects exhibit static electricity?

Four balls, each with mass m, are connected by four nonconducting strings to form a square with side a as shown in Figure P25.74. The assembly is placed on a nonconducting. frictionless. horizontal surface. Balls 1 and 2 each have charge q, and balls 3 and 4 are uncharged. After the string connecting halls 1 and 2 is cut, what is the maximum speed of balls 3 and 4?

Assume the charged objects in Figure OQ23.10 are fixed. Notice that there is no sight line from the location of q2 to the location of q1. If you were at q1, you would be unable to see q2 because it is behind q3. How would you calculate the electric force exerted on the object with charge q1? (a) Find only the force exerted by q2 on charge q1. (b) Find only the force exerted by q3 an charge q1. (c) Add the force that q2 would exert by itself on charge q1 to the force that q3 would exert by itself on charge q1. (d) Add the force that q3 would exert by itself to a certain fraction of the force that q2 would exert by itself. (e) There is no definite way to find the force on charge q1.