Physics 101 Ch. 12 Electrostatics

A uniform electric field has a magnitude of 10 N/C and is directed upward. A charge brought into the field experiences a force of 5.0 N downward. The charge must be: +0.5 C. -50 C. +50 C. -2.0 C. -0.5 C.

-0.5 C.

Two charged particles exert an electrostatic force of 6 N on each other. What will the magnitude of the force be if the distance between the two particles is increased to four times the original distance?

0.375 N

Two equal charges repel one another with a force of 4.00 10-4 N when they are 10 cm apart. If they are moved until the separation is 5.0 cm, the repulsive force will be: 1.6 X 10^-3 N. 8.00 X 10^-4 N. 4.00 X 10^-4 N. 2.00 X 10^-4 N. 1.00 X 10^-4 N.

1.6 X 10^-3 N

An electron has a charge of -1.6 10-19 C. How many electrons would be needed to produce a net charge of -4.10 10-7 C?

2.56e12

The potential energy of a +7.0 10-6 C charge decreases from 0.17 J to 0.02 J when it is moved from point A to point B. What is the change in electric potential between these two points?

21, 428.6 V

A charge of −0.15 C is moved from a position where the electric potential is 20 V to a position where the electric potential is 60 V. What is the change in potential energy of the charge associated with this change in position?

6 J

If the distance between two charged objects is doubled, will the electrostatic force that one object exerts on the other be cut in half? Explain. Yes, since the Coulomb force varies inversely as the distance between the charges, doubling the distance reduces the force by a factor of one-half. Yes, since the Coulomb force varies exponentially between the charges, doubling the distance increases the force by a factor of 2. No, since the Coulomb force varies as the square of the distance between the charges, doubling the distance increases the force by a factor of 4. No, since the Coulomb force varies inversely as the square of the distance between the charges, doubling the distance reduces the force by a factor of one-fourth.

No, since the Coulomb force varies inversely as the square of the distance between the charges, doubling the distance reduces the force by a factor of one-fourth.

Is the electric field produced by a single positive charge a uniform field? Explain. Yes, the electric field from a single positive charge is uniform in all directions, producing a region of uniform field. No, the electric field lines from the charge diverge with increasing distance, indicating a field that decreases in strength with distance. No, the electric field lines converge on the charge, producing a field of increasing strength as the distance to the charge decreases.

No, the electric field lines from the charge diverge with increasing distance, indicating a field that decreases in strength with distance.

Can both the electrostatic force and the gravitational force be either attractive or repulsive? Explain. Yes, both the force between charges and the gravitational force between matter can be either attractive or repulsive. No, the gravitational force between matter can be either attractive or repulsive but the force between charges is always attractive. No, the force between charges can be either attractive or repulsive but the gravitational force between matter is always attractive. No, the force between charges is always repulsive and the gravitational force between matter is always attractive.

No, the force between charges can be either attractive or repulsive but the gravitational force between matter is always attractive.

If two charges are both doubled in magnitude without changing the distance between them, will the force that one charge exerts on the other also be doubled? Explain. Yes, the force between the two charges will be doubled since the Coulomb force between the charges varies as the magnitude of the two charges and doubling each gives a two-fold increase. No, the force between the two charges will be halved since the Coulomb force between the charges varies inversely as the magnitude of the two charges and doubling each gives a two-fold decrease. No, the force between the two charges will be one-fourth the original since the Coulomb force between the charges varies inversely as the product of the two charges and doubling each gives a four-fold decrease. No, the force between the two charges will be quadrupled since the Coulomb force between the charges varies as the product of the two charges and doubling each gives a four-fold increase.

No, the force between the two charges will be quadrupled since the Coulomb force between the charges varies as the product of the two charges and doubling each gives a four-fold increase.

Will bits of paper be attracted to a charged rod even if they have no net charge? Explain. Yes, the bits of paper become polarized by the charged rod so that the side of the bit of paper near the rod takes on a charge opposite to the sign of charge on the rod. Yes, the bits of paper become superconductors and absorb electrons from the ions in air. No, the bits of paper become polarized by the charged rod so that the side of the bit of paper near the rod takes on a charge identical to the sign of charge on the rod. No, the bits of paper are electrically neutral and there is no attraction between a neutral object and a charged rod.

Yes, the bits of paper become polarized by the charged rod so that the side of the bit of paper near the rod takes on a charge opposite to the sign of charge on the rod.

If the potential at point A is one volt it means that: an electron at A can perform one joule of work. a charge at A has potential energy one joule for each coulomb of charge. an object at A has charge equal to one coulomb. there is a small battery present.

a charge at A has potential energy one joule for each coulomb of charge.

An electron situated near another electron would feel: an attractive magnetic force. a repulsive magnetic force. a repulsive electrical force. an attractive electrical force. no forces from the other electron.

a repulsive electrical force.

Two equal positive charges are near each other. If we increase the amount of charge on just one of them, then: (Select all that apply.) a)both charges feel an increased electrical force. b)the electric field felt by both charges increases. c)the electric field felt by the smaller charge increases. d)only smaller charge feels an increased electrical force. e)None of these are true.

a)both charges feel an increased electrical force. c)the electric field felt by the smaller charge increases

An atom has: a)no neutrons in the nucleus. b)just as many electrons as protons. c)more protons than electrons. d)at least 1 neutron. e)as many electrons as protons and neutrons combined.

b)just as many electrons as protons.

If the distance between two spherical charged objects increases by a factor of two, then the electrical force between the objects: does not change. doubles. is half as big. increases by a factor of four. decreases by a factor of four.

decreases by a factor of four.

Compared to the magnitude of the charge on a proton, the magnitude of the electrical charge carried by an electron is: about the same. exactly the same. is only 1/2 as large. is only 1/3 as large.

exactly the same.

The three processes by which heat energy is transferred between objects are: radiation, absorption, and conduction. heat, calorie and radiation. absorption, radiation, and convection. radiation, convection, and conduction. radiation, temperature, and convection.

radiation, convection, and conduction.

The electrical force between two charged objects depends on: the amount of combined charge of both objects. the color of the objects. the amount of charge on each of the two objects. which object has the greatest charge. the mass of the objects.

the amount of charge on each of the two objects.

After a glass rod is rubbed with a nylon cloth: the rod will have a positive charge and the cloth negative. both the rod and cloth will have a negative charge. the rod will have a negative charge and the cloth will be neutral. both the rod and cloth will have a positive charge. the rod will have a negative charge and the cloth positive.

the rod will have a positive charge and the cloth negative.