Download AP B Physics Chapter 18 Electrostatics #2

AP B Physics Chapter 18 Electrostatics #2
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1. Only one of three balls A, B, and C carries a net charge q. One of the uncharged balls can
become charged by touching it to the charged ball and then separating the two. This process
of touching one ball to another and then separating the two balls can be repeated over and
over again, with the result that the three balls can take on a variety of charges. Which one of
the following distribution of charges could not possibly be achieved in this fashion?
A.
=
,
=
,
=
B.
=
,
=
,
=
****C.
D.
=
=
,
,
=
=
,
,
=
=
2. You have two identical metal spheres and a negatively charged ebonite rod. Without
touching the rod to the spheres, which one of the following procedures can you use to give
each sphere a net electrical charge of the same magnitude, one being positive and the other
being negative?
A. Bring the two spheres near each other, but do not allow them to touch. Bring the rod into
the space between the spheres. Then, with the rod in place, separate the spheres.
B. Bring the two spheres close together, but do not allow them to touch. Bring the rod near
one sphere, opposite the space between the spheres. Then, with the rod in place, separate the
spheres.
**C. Touch the two spheres together. Bring the rod near one sphere, opposite the place where
the spheres are touching. Then, with the rod in place, separate the spheres.
D. Touch the two spheres together. Bring the rod near one sphere, opposite the place where
the spheres are touching. Then, remove the rod. Finally, separate the spheres.
3. Three point charges have equal magnitudes and are fixed to the corners of
an equilateral triangle. Two of the charges are positive and one is negative,
as the drawing shows. At which one of the corners is the net force acting on
the charge directed parallel to the x axis?
A
***B
C
4. Because of an electric field, a positive charge +q experiences a force of
magnitude F that points due west. The positive charge is then replaced with a
negative charge -2q. What force does the negative charge experience?
A.The negative charge experiences no force, because electric fields only exert forces on
positive charges.
B. Force magnitude = F, force direction is due east
C. Force magnitude = F, force direction is due west
D. Force magnitude = 2F, force direction is due west
***E. Force magnitude = 2F, force direction is due east
5. A positive point charge q1 creates an electric field of magnitude E1 at a
spot located at a distance r1 from the charge. The charge is replaced by
another positive point charge q2, which creates a field of
magnitude E2 = E1 at a distance of r2 = 2r1. How is q2 related to q1?
A.
B.
***C.
D.
E.
6. The drawing shows a positive and a negative point charge. The negative charge has the
greater magnitude. Where on the line that passes through the charges is the one spot where
the total electric field is zero?
To the right of the negative charge.
**To the left of the positive charge.
Between the charges, to the left of the midpoint.
Between the charges, to the right of the midpoint.
7. Three point charges (some positive and some negative) are fixed to the corners of the same
square in various ways, as the drawings show. Each charge, no matter what its algebraic sign,
has the same magnitude. In which arrangement (if any) does the net electric field at the
center of the square have the greatest magnitude?
A
B
C
D
***The magnitude of the net field at the center of the square is the same in each
arrangement of the charges.
8. One mole of a substance contains 6.02 x 1023 protons and an equal
number of electrons. If the protons could somehow be separated from the
electrons and placed in separate containers separated by 1.00 x 103 m, what
would be the magnitude of the electrostatic force exerted by one box on the
other?
A)
8.7 x 108 N
B)
9.5 x 109 N
C)
2.2 x 1010 N
***D)
8.3 x 1013 N
E)
1.6 x 1019 N
9. Four point charges, each of the same magnitude, with varying signs are arranged at
the corners of a square as shown. 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.
**B.
C.
D.
E.
A
B
C
D
The net force on that charge is zero.
10.
Three charges are positioned as indicated in the figure. What are the horizontal
and vertical components of the net force exerted on the +15 µC charge by the +11 µC and
+13 µC charges?
horizontal
vertical
A.
95 N
310 N
B.
76 N
310 N
C.
250 N
130 N
D.
95 N
130 N
***E.
76 N
370 N
11.
In Frame 1, two identical conducting spheres, A and B, carry equal amounts of
excess charge that have the same sign. The spheres are separated by a distance d; and
sphere A exerts an electrostatic force on sphere B that has a magnitude F. A third
sphere, C, which is handled only by an insulating rod, is introduced in Frame 2.
Sphere C is identical to A and B except that it is initially uncharged. Sphere C is touched
first to sphere A, in Frame 2, and then to sphere B, in Frame 3, and is finally removed in
Frame 4.
Determine the magnitude of the electrostatic force that sphere A exerts on sphere B in
Frame 4.
A.
F/2
B.
F/3
C.
3F/4
***D. 3F/8
E.
zero
12.
Three charges are located along the x axis as shown in the drawing. The mass of
the 1.2 µC charge is 4.0 × 109 kg. Determine the magnitude and direction of the
acceleration of the 1.2 µC charge when it is allowed to move if the other two charges
remain fixed.
-5
A.
**B.
C.
D.
E.
-4 -3
-2 -1
0
1
2
3
4
5
6
7
8
9
2.1 × 105 m/s2, to the right
3.7 × 104 m/s2, to the right
7.0 × 104 m/s2, to the right
3.0 × 105 m/s2, to the left
4.0 × 106 m/s2, to the right
13.
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
14. Five particles are shot from the left into a region that contains a uniform electric
field. The numbered lines show the paths taken by the five particles. A negatively
charged particle with a charge 3Q follows path 2 while it moves through this field.
In which direction does the electric field point?
A. toward the top of the page
B. toward the left of the page
C. toward the right of the page
**D.
toward the bottom of the page
E. out of the page, toward the reader
15. Two point charges, A and B, lie along a line separated by a distance L. The
point x is the midpoint of their separation.
Which combination of charges will yield zero electric field at the point x ?
A.
B.
C.
D.
**E.
+1q and 1q
+2q and 3q
+1q and 4q
1q and +4q
+4q and +4q