CH 19

The electric field lines surrounding three charges: q1, q2, q3. The center charge is q2 = -8.00μC . Find q1 and q3

4.00

<--A(+q)---B--C--D---(-2q)--E--> For the charge distribution provided, indicate the region (A to E) along the horizontal axis where a point exists at which the net electric field is zero.

A

Which are true? A. Electric field lines can never intersect. B. At every point in space, the electric field vector at that point is tangent to the electric field line through that point. C. Electric field lines are continuous; they do not have a beginning or an ending. D. Electric field lines point away from positive charges and toward negative charges. E. Electric field lines are close together in regions of space where the magnitude the electric field is weak and are father apart where it is strong.

A. Electric field lines can never intersect. B. At every point in space, the electric field vector at that point is tangent to the electric field line through that point. D. Electric field lines point away from positive charges and toward negative charges.

The strength of the electric field at a certain distance from a point charge is represented by E. What is the strength of the electric field at twice the distance from the point charge? At twice the distance, the strength of the field is 4E. At twice the distance, the strength of the field is E/4. At twice the distance, the strength of the field is 2E. At twice the distance, the strength of the field remains equal to E. At twice the distance, the strength of the field is E/2.

At twice the distance, the strength of the field is E/4

<--A(+q)---B--C--D---(+2q)--E--> For the charge distribution provided, indicate the region (A to E) along the horizontal axis where a point exists at which the net electric field is zero.

B

<--A(+q)---B-C-D---(+q)--E--> For the charge distribution provided, indicate the region (A to E) along the horizontal axis where a point exists at which the net electric field is zero.

C

An electrically neutral object is given a positive charge. In principle, does the object's mass increase, decrease, or stay the same as a result of being charged?

Decrease (To give the object a positive charge we must remove some of its electrons; this will reduce its mass.)

What is the equation for Energy Field?

E = k(q/r^2)

What is the Relationship between Coulomb's Law and Energy Fields?

F=Eq

What is Coulomb's Law?

F=k(qq/r^2)

An electrically neutral object is given a negative charge. In principle, does the object's mass increase, decrease, or stay the same as a result of being charged?

Increase (To give the object a negative charge we must give it more electrons, and this will increase its mass.)

B | | +q A +q A charge +q is to be placed at either point A or point B in the accompanying figure. Assume points A and B lie on a line that is midway between the two positive charges. Is the net force experienced at point A greater than, equal to, or less than the net force experienced at point B?

Less than (The net force at point A cancels. Therefore, the nonzero net force at point B is greater in magnitude than the zero net force at point A.)

After several contacts with the charged ball, how is the charge on the rod arranged?

Negative charge on end A with end B remaining almost neutral

<--A(+q)---B--C--D---(-q)--E--> For the charge distribution provided, indicate the region (A to E) along the horizontal axis where a point exists at which the net electric field is zero.

No where. (The net electric field can only be zero if the electric fields due to the two charges point in opposite directions and have equal magnitudes.)

When a point charge of +q is placed on one corner of a square, an electric field strength of 2 N/C is observed at the center of the square. Suppose three identical charges of +q are placed on the remaining three corners of the square. What is the magnitude of the net electric field at the center of the square?

The magnitude of the net electric field at the center of the square is 0 N/C

A small metal ball is given a negative charge, then brought near to end A (2 negative charges, 1 positive) of the rod. What happens to end A of the rod when the ball approaches it closely this first time?

Weakly Attracted

Is it possible for the electric field between two positive charges to equal zero along the line joining the two charges?

Yes, regardless of the magnitude of the two charges.

<--A(-q)---B(+q)---C(+q)--> Identify the regions in which you can find E=0 at a finite distance from the charges. A. between points A and B B. between points B and C C. to the left of point A D. to the right of point C

between points B and C; to the left of point A

An object with a negative charge experiences an upward electric force, due to a uniform electric field, equal in magnitude to its weight, Find the direction of the electric field.

downward. ( A negative charge is always pulled in a direction opposite the electric field. )