Electric Charge
Electric charges A and B are attracted to each other. Electric charges B and C
repel each other. If A and C are held close together they will
(A) Attract.
(B) Repel.
(C) Not affect each other
(D) More information is needed to
answer.
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CHAPTER 1
ELECTRIC CHARGE AND COULOMB’S LAW
Electric charges A and B are attracted to each other. Electric charges B and C
are also attracted to each other. If A and C are held close together they will
(A) Attract.
(B) Repel.
(C) Not affect each other
(D) More information is needed to
answer.
3.
Electric charges A and B repel each other. Electric charges B and C also repel
each other. If A and C are held close together they will
(A) Attract.
(B) Repel.
(C) Not affect each other
(D) More information is needed to
answer.
PH
2.
If an object made of substance A rubs an object made of substance B, then A
becomes positively charges and B becomes negatively charged. If, however,
an object made of substance A is rubbed against an object made of substance
C, then A becomes negatively charged. What will happen if an object made of
substance B is rubbed against an object made of substance C?
(A) B becomes positively charged and C becomes positively charged.
(B) B becomes positively charged and C becomes negatively charged.
(C) B becomes negatively charged and C becomes positively charged.
(D) B becomes negatively charged and C becomes negatively charged.
A positively charged rod is held near a ball suspended by an insulating thread.
The ball is seen to swing toward the charged rod. What can be concluded?
(A) The ball must have had a charge opposite to that of the rod.
(B) The ball may have been neutral originally, but it became charged when the
rod was held near it.
(C) The ball must be conductor.
(D) The ball is not positively charged, but it could be neutral.
PR
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4.
A
Conductors and Insulators
6.
A spherical conducting ball is suspended by a grounded conducting thread. A
positive point charge is moved near the ball. The ball will
A spherical conducting ball is suspended by an insulating thread. A positive
point charge is moved near the ball. The ball will
(A) be attracted to the point charge and swing towards it.
(B) be repelled from the point charge and swing away from it.
(C) not be affected by the point charge.
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(A) be attracted to the point charge and swing towards it.
(B) be repelled from the point charge and swing away from it.
(C) not be affected by the point charge.
Coulomb’s Law
A 3-µC point charge q 1 is located a distance d away from a – 6-µC point charge


q 2 . What is the ratio F12 / F21
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8.
(A) 1/2
(C) 2
(B) 1
(D) 18
Two 200-pound lead balls are separated by a distance of 1 m. Both balls have
the same positive charge q. What charge will produce an electrostatic force
between the balls that is of the same order of magnitude as the weight of one
ball?
(A) 1 × 10-14 C
(B) 1 × 10-7 C
(C) 3 × 10-4 C
(D) 2 × 10-2 C
10.
Two identical, small, conducting spheres are separated by a distance of 1 m.
The spheres originally have the same positive charge, and the force between
them is F 0 . Half of the charge on one sphere is then moved to the other sphere.
The force between the spheres is now
(B) F 0 /2.
(A) F 0 /4.
(C) 3F 0 /4.
(D) 3F 0 /2.
(E) 3F 0 .
Two identical, small conducting spheres are separated by a distance of 1 m.
The spheres originally have equal but opposite charges, and the force between
them is F 0 . Half of the charge on one sphere is then moved to the other sphere.
The force between the spheres is now
(A) F 0 /4.
(B) F 0 /2.
(C) 3F 0 /4.
(D) 3F 0 /2.
(E) 3F 0 .
PR
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A
9.
12.
Three charged particle are in equilibrium under their electrostatic forces only.
(A) the particles must be collinear.
(B) All the charges cannot have the same magnitude.
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(C) All the charges cannot have the same sign.
(D) The equilibrium is unstable.
Two identical charges +Q are kept fixed some distance apart. A small particle
P with charge q is placed midway between them. If P is given a small
displacement ∆, it will undergo simple harmonic motion if
(A) q is positive and ∆ is along the line joining the charges.
(B) q is positive and ∆ is perpendicular to the line joining the charges.
(C) q is negative and ∆ is perpendicular to the line joining charges.
(D) q is positive and ∆ is along the line joining the charges.
14.
A particle A of mass m and charge Q moves directly towards a fixed particle B,
which has charge Q. The speed of A is v when it is far away from B. The
minimum separation between the particles is proportional to
(A) Q2
(C)
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(B)
1
v
(D)
Conservation of Change
1
v2
1
m
A positively charged rod is held near a neutral conducting sphere suspended
by an insulating thread. The sphere will
(A) be unaffected, because it is neutral.
(B) remain neutral, but be repelled from the rod anyway.
(C) remain neutral, but be attracted to the rod anyway.
(D) acquire a negative charge and be repelled from the rod.
(E) acquire a negative charge and be attracted to the rod.
16.
Objects A, B and C are three identical, insulated, spherical conductors.
Originally A and B both have charges of +3 mC, while C has a charge of – 6
mC. Objects A and C are allowed to touch, then they are moved apart. Then
objects B and C are allowed to touch, and they are moved apart.
CI
If object A and B are now held near each other, they will
(A) attract.
(B) repel.
(C) have no effect on each other.
IN
(a)
PI
A
15.
If object A and C are held near each other, they will
(A) attract.
(B) repel.
(C) have no effect on each other.
PR
(b)
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A
B
B
C
D, (B)
C
A
B
C
C
A
A, B, C, D
A, C
A, B, D
C
(a)----A (b) ------A
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