Transcript here are the answers

Electricity Review
1) A neutral piece of fur is rubbed along a neutral
plastic rod. The rod gains a charge of +4.0 mC. Which
of the following is true?
A)
B)
C)
D)
E)
The fur gains a charge of +4.0 mC
The protons moved from the rod to the fur.
The fur has gained electrons.
The rod and fur now repel.
This is an example of charging by contact.
2. The neutral rod gained a charge of +4.0 mC. Which
of the following statements is true?
A)
B)
C)
D)
E)
The rod lost 2.5*1013 electrons
The rod lost 2.5*1019 electrons
The rod lost 4.0*10-6 electrons
The rod lost 4.0*106 electrons
The rod lost 6.4*10-25 electrons
3. Two identical conducting spheres are charged.
Sphere A has a charge of +2μC and sphere B has a
charge of -8μC. The two spheres touch each other.
Which best describes what happened.
A) Negative charge moved from sphere B to sphere A until
sphere B had a net charge of zero.
B) Positive charge moved from Sphere A to sphere B until
sphere A had a net charge of zero.
C) Negative charge moved from sphere B to sphere A until
the two spheres had equal charge.
D) Positive charge moved from sphere A to sphere B until
the two spheres had equal charge.
E) Negative charge moved from sphere B to sphere A and
positive charge moved from sphere A to sphere B until
the two spheres had equal charge.
4. Two identical conducting spheres are charged.
Sphere A has a charge of +2.00μC and sphere B has
a charge of -8.00μC. The two spheres touch each
other and then are pulled apart. To make sphere A
neutral you should:
A)
B)
C)
D)
E)
Add 3.75 x 1013 electrons
Remove 3.75 x 1013 electrons
Add 1.88 x 1013 electrons
Remove 1.88 x 1013 electrons
Do nothing – the sphere is already neutral.
5. Three charges are aligned as shown below.
-3.0 mC
0.30 m
+2.0 mC
+4.0 mC
0.30 m
What is the magnitude of the force on the +2.0 mC
charge?
A) 1.4 N
B) 0.80 N
C) 0.60 N
D) 0.20 N
E) 0 N
6. Two charges are aligned as shown below.
-3.0 mC
0.30 m
+4.0 mC
Point X
0.30 m
What is the electric field at point X?
A)
B)
C)
D)
E)
0 N/C
1.0*105 N/C to the left
3.0*105 N/C to the left
4.0*105 N/C to the left
7.0*105 N/C to the left
7. Which of the following statement is false?
A) A positive charge experiences a force in the
direction of the electric field.
B) A positive charge moving against the electric field
gains electric potential energy.
C) Electric field lines never cross.
D) Electric field lines start at a negative or infinity.
E) The density of electric field lines is related to the
strength of the electric field
8. A parallel plate capacitor has an electric field of 0.50
N/C in the direction shown below.
E
Which is the positive of the two plates?
A)
B)
C)
D)
E)
The top plate.
The bottom plate.
It depends on the type of charge placed between the plates.
It depends on the distance between the plates.
They both have the same charge.
9. A parallel plate capacitor has an electric field of 0.50
N/C in the direction shown below.
E
Where would a charge have the highest EPE due to the
electric field?
A)
B)
C)
D)
E)
At the top plate.
At the bottom plate.
Directly between the plates.
It depends on the type of charge placed between the plates.
The charge has no EPE anywhere between the plates
10. A parallel plate capacitor has an electric field of
0.50 N/C in the direction shown below.
E
What charge should a 2.5*10-5 kg drop of oil have to
stay suspended between the plates? (Include gravity)
A)
B)
C)
D)
E)
+5.0*10-5 C
+5.0*10-4 C
-5.0*10-5 C
-5.0*10-4 C
-1.3*10-4 C
11. The resistance of a bagel toaster is 15 Ω. To
prepare a bagel, the toaster is plugged into a standard
120-V outlet.
How much power does the toaster consume?
A)
B)
C)
D)
E)
8.0 W
15 W
120 W
960 W
1800 W
12. The resistance of a bagel toaster is 15 Ω. To
prepare a bagel, the toaster is plugged into a standard
120-V outlet.
Find the energy consumed in the 1.5 minutes it takes to
toast a bagel.
A)
B)
C)
D)
E)
1.4 J
180 J
1400 J
11000 J
86000 J
13. The resistance of a bagel toaster is 15 Ω. To
prepare a bagel, the toaster is plugged into a standard
120-V outlet.
How much charge passes through the toaster in 1.5
minutes?
A)
B)
C)
D)
E)
12 C
120 C
720 C
960 C
86000 C
14. You are given two resistors with different
resistances and a battery. Indicate which circuit
arrangement best answers the question.
Which arrangement has the greatest total resistance?
A) Series
B) Parallel
C) Same for both
15. You are given two resistors with different
resistances and a battery. Indicate which circuit
arrangement best answers the question.
Which arrangement has the same current in each
resistor?
A) Series
B) Parallel
C) Same for both
16. You are given two resistors with different
resistances and a battery. Indicate which circuit
arrangement best answers the question.
Which arrangement draws the greatest current from
the battery?
A) Series
B) Parallel
C) Same for both
17. You are given two resistors with different
resistances and a battery. Indicate which circuit
arrangement best answers the question.
Which arrangement has the same voltage drop across
each resistor?
A) Series
B) Parallel
C) Same for both
18. You are given two resistors with different
resistances and a battery. Indicate which circuit
arrangement best answers the question.
Which arrangement uses up the battery faster?
A) Series
B) Parallel
C) Same for both
19. The current in a 47-Ω resistor is 0.12 A. This
resistor is in series with a 28-Ω resistor, and the
series combination is connected across a
battery. What is the battery voltage?
a)
b)
c)
d)
5.6 V
3.4 V
9.0 V
4.5 V
20.The current in a series circuit is 15.0 A. When
an additional 8.00-Ω resistor is inserted in
series, the current drops to 12.0 A. What is
the resistance in the original circuit?
A)
B)
C)
D)
8.00-Ω
24.0-Ω
32.0-Ω
40.0-Ω
21. Two identical light bulbs are connected to identical batteries in
two different ways. In method A the bulbs are connected in
parallel, and the parallel combination is connected between
the one battery's terminals. In method B the bulbs are
connected in series, and the series combination is connected
between the other battery's terminals. What is the ratio of the
power supplied by the battery in method A to the power
supplied in method B?
A)
B)
C)
D)
¼
4
½
1
22.Two resistors, 42.0 and 64.0 Ω, are connected
in parallel. The current through the 64.0-Ω
resistor is 3.00 A. Determine the current in
the other resistor.
a.
b.
c.
d.
e.
1.97 A
3.00 A
4.57 A
4.97 A
7.57 A
23. Two resistors, 42.0 and 64.0 Ω, are
connected in parallel. The current through the
64.0-Ω resistor is 3.00 A. What is the total
power supplied to the two resistors?
a.
b.
c.
d.
e.
192 W
318 W
576 W
877 W
1450 W