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Chapter 22 Electrostatics
1) A main difference between gravitational and electric forces is
that electrical forces
A) obey the inverse-square law.
B) act over shorter distances.
C) are weaker.
D) repel or attract.
E) attract.
2)
A)
B)
C)
D)
Every proton in the universe is surrounded by its own
electric field.
gravitational field.
both of these.
none of these.
3) Charge carriers in a metal are electrons rather than protons
because electrons are
A) smaller.
B) loosely bound.
C) negative.
D) all of these.
E) none of these.
4) You can touch a 100,000-volt Van de Graaff generator with
little harm because although the voltage is high, the relatively small
amount of charge means there is a relatively small amount of
A) polarization.
B) energy.
C) electric field.
D) conduction.
5) Two charges separated by one meter exert 1-N forces on each
other. If the charges are pulled to 3-m separation distance, the
force on each charge will be
A) 0.33 N.
F = k Q q / r2
B)
C)
D)
E)
0.11 N.
0 N.
3 N.
9 N.
F ∝ 1/r2
6) Two charged particles repel each other with a force F. If the
charge of one of the particles is doubled and the distance between
them is also doubled, then the force will be
A) F/2.
F = k Q q / r2
B) F.
F = k Q 2q / (2r)2
C) 2 F.
F = k Q 2q / 4r2
D) F/4.
E) none of these.
7) When a single charge q is placed at one corner of a square, the
electric field at the center of the square is F/q. If two other equal
charges are placed at the adjacent corners of the square, the
electric field at the center of the square due to these three equal
charges is
A) F/q.
B) F/(4q).
C) F/(2q).
D) 4F/q.
E) none of these.
8) Two charged particles held near each other are released. As
they move, the acceleration of each decreases. Therefore, the
particles have
A) the same sign.
B) opposite signs.
C) not enough information given.
9)
A)
B)
C)
D)
A capacitor is used to store
charge.
energy.
both.
neither.
Chapter 23 Electric Current
10) Two lamps, one with a thick filament and one with a thin
filament, are connected in series. The current is greater in the lamp
with the
A) thick filament.
B) thin filament.
C) the same in each lamp.
11) As more lamps are put into a series circuit, the overall current
in the power source
A) decreases.
More lamps…more resistance
B) stays the same.
Give credit for A&B
C) increases.
12) When we say an appliance such as a toaster "uses up
electricity," we really are saying that
A) electrons are taken out of the circuit and put somewhere else.
B) electric charges are dissipated.
C) the main power supply voltage is lowered.
D) current disappears.
E) electron kinetic energy is changed into heat.
13) Which is more dangerous, touching a faulty 110-volt light
fixture, or a Van de Graaff generator charged to 100,000 volts?
Touching the
A) light fixture.
B) generator.
C) both about equally dangerous.
14) A heater uses 20 A when used in a 110-V line. If electric power
costs 10 cents per kilowatt hour, the cost of running the heater for
10 hours is
A) $0.22.
P= I V
B) $0.55.
P = 20A(110V)
C) $2.20.
P = 2200 W
D) $5.50.
E = P (t)
E) none of these.
E = 2200W (10 hr)
E = 22 kW-hr  $2.20
15) Compared to the amount of electric current in the filament of
a lamp, the amount of current in the connecting wire is
A) definitely less.
B) often less.
C) the same.
D) actually more.
E) incredibly, all of these.