PHY 213 Exam 1

If a positive test charge is placed at each of the three points, which point experiences the strongest electric field? And which point experience the weakest electric field?

strongest at A, weaker at B, zero at C

Two charges, one positive and the other negative, are initially 2 cm apart and are then pulled away from each other until they are 6 cm apart. The force between them is now smaller by a factor of a. 9 b. 3 c. 27 d. sqrt 3

a. 9

Two positive point charges Q and 2Q are separated by a distance R. If the charge Q experiences a force of magnitude F when the separation is R, what is the magnitude of the force on the charge 2Q when the separation is 2R? a. F/4 b. F/2 c. F d. 2F e. 4F

a. F/4

Four point charges, each of the same magnitude, with varying signs are arranged at the corners of a square. Which of the arrows labeled A, B, C, and D gives the correct direction of the net force that acts on the charge at the upper right corner? a. A b. B c. C d. D e. the net force on that charge is zero

b. B

Object A has a charge of +2 uC, and object B has a charge of +6 uC. Which statement is true: a. Fab = -3Fba b. Fab = -Fba c. 3Fab = -Fba

b. Fab = -Fba

An object has a positive electric charge whenever a. it has an excess of electrons b. it has a deficiency of electrons c. the nuclei of its atoms are positively charged d. the electrons of its atoms are positively charged

b. it has a deficiency of electrons

A conducting sphere has a net charge of -4.8e-17 C. What is the approximate number of excess electrons on the sphere? a. 100 b. 200 c. 300 d. 400 e. 500

c. 300 electrons

A charge of +q is placed 2 cm from a charge of -Q. A second charge of +q is then placed next to the first. The force on the charge of -Q a. decreases to half its former magnitude b. remains the same c. increases to twice its former magnitude d. increases to four times its former magnitude

c. increases to twice its former magnitude

A negative electric charge a. interacts only with positive charges b. interacts only with negative charges c. interacts with both positive and negative charges d. may interact with either positive and negative charges, depending on circumstances

c. interacts with both positive and negative charges

Electric charge a. is a continuous quantity that can be subdivided indefinitely b. is a continuous quantity but it cannot be subdivided into smaller parcels than 1.6e-19 C c. occurs only in separate parcels, each of 1.6e-19 C d. occurs only in separate parcels, each of 1 C

c. occurs only in separate parcels, each of 1.6e-19 C

The charges of +Q are 1 cm apart. If one of the charges is replaced by a charge of -Q, the magnitude of the force between them is a. zero b. smaller c. the same d. larger

c. the same

An electron traveling horizontally enters a region where a uniform electric field is directed upward. What is the direction of the force exerted on the electron once it has entered the field? a. to the left b. to the right c. upward d. downward e. out of the page, toward the reader

d. downward

Two particles of the same mass carry charges +3Q and -2Q, respectively. They are shot into a region that contains a uniform electric field as shown. The particles have the same initial velocities in the positive x direction. The lines numbered 1 through 5, indicate possible paths for the particles. If the electric field points in the negative y direction, what will be the resulting paths for these particles? a. path 1 for +3Q and path 4 for -2Q b. path 3 for +3Q and path 2 for -2Q c. path 4 for +3Q and path 3 for -2Q d. path 2 for +3Q and path 5 for -2Q e. path 5 for +3Q and path 2 for -2Q

e. path 5 for +3Q and path 2 for -2Q