AP Physics
Current and Circuits
Sample MC
1.
Current
(A) is the rate of charges passing a point.
(B) is the movement of charges caused by the force of an
electric field.
(C) flows when there is a conducting path and a potential
difference between the ends.
(D) is measured in Amperes.
(E) All of these are correct.
8.
If I were shown graphs representing the three problems
above, I
(A) would know what they look like.
(B) have no clue. I never learned what direct and indirect
look like.
(C) What was the question?
(D) Huh?
(E) There is a test today?
2.
The electric field moves through the circuit at the speed of
light. Which describes the resulting motion of charges in
the circuit?
(A) The charges accelerate with the field, and with no
resistance they could eventually reach the speed of
light.
(B) The charges encounter obstacles in the wire known as
resistivity, which is the electrical equivalent of friction.
(C) The obstacles cause collisions with the charges
generating heat (like friction does in mechanics), and
the collisions cause random motion of the charges.
(D) The heat from the collisions caused even more random
motion, which increases as the wires become even
hotter.
(E) The charges accelerate forward with the field, bounce
back, then forward again.
(F) A general drift of charge from the positive plate of the
battery to the negative plate occurs and resembles the
motion of a ball in a pinball machine.
(G) The slowing caused by the collisions results in a
velocity that is just centimeters per second.
(H) All of these.
9.
The power company bills you in kW·hr’s. What are they
selling?
(A) Power
(D) electric field
(B) electric force
(E) electric potential
(C) electric energy
3.
4.
Which of the following values increases resistance
I. increasing temperature
II. increasing the wires diameter
III. increasing the wires length
IV. selecting a material with a lower resistivity
(A) I and III.
(D) I, III, and IV
(B) I, II, and III
(E) All of these.
(C) I, II, and IV
Which wire would have the most resistance?
(A) thin, short, high resistivity, and warm
(B) thick, short, low resistivity, and warm
(C) thin, long, high resistivity, and cool
(D) thick, long, low resistivity, and cool
(E) thin, long, high resistivity, and warm
5.
The relationship between current and resistance in Ohm’s
Law is
(A) directly proportional.
(C) Neither of these.
(B) inversely proportional.
6.
The relationship between current and potential in Ohm’s
Law is
(A) directly proportional.
(C) Neither of these.
(B) inversely proportional.
7.
The relationship between potential and resistance in Ohm’s
Law is
(A) directly proportional.
(C) Neither of these.
(B) inversely proportional.
10. A light bulb uses 30 W when connected to 3 V battery. If it
is connected to a 6 V battery it will use
(A) 30 W
(D) 120 W
(B) 60 W
(E) 150 W
(C) 90 W
11. If you want a brighter light to read your Physics book by at
night, then you must find a bulb that
(A) has less resistance, so it allows less current to flow
through it at the same voltage, resulting in a lower rate
of energy dissipation.
(B) has less resistance, so it allows more current to flow
through it at the same voltage, resulting in a higher rate
of energy dissipation.
(C) has less resistance, so it allows more current to flow
through it at the same voltage, resulting in a lower rate
of energy dissipation.
(D) has more resistance, so it allows less current to flow
through it at the same voltage, resulting in a lower rate
of energy dissipation.
(E) has more resistance, so it allows more current to flow
through it at the same voltage, resulting in a higher rate
of energy dissipation.
12. You have three 3 ohm resistors. What are the minimum and
maximum resistances that can be achieved using all three
resistors
(A) 1 Ω and 3 Ω.
(D) 1.5 Ω and 6 Ω.
(B) 1 Ω and 9 Ω.
(E) 3 Ω and 9 Ω.
(C) 1.5 Ω and 6 Ω.
13. Kirchhoff’s junction rule states that the
(A) charge entering a junction equals the charge leaving a
junction and implies that current adds in parallel.
(B) charge entering a junction equals the charge leaving a
junction and implies that current stays the same in
parallel.
(C) charge entering a junction equals the charge leaving a
junction and implies that current adds in series.
(D) potential entering a junction equals the potential
leaving a junction and implies that current adds in
parallel.
(E) potential entering a junction equals the potential
leaving a junction and implies that current stays the
same in parallel.
14. Kirchhoff’s loop rule states that the net
(A) potential in any loop of a circuit equals zero, and
implies that potential adds in parallel.
(B) potential in any loop of a circuit equals zero, and
implies that potential adds in series.
(C) current in any loop of a circuit equals zero, and implies
that current adds in parallel.
(D) current in any loop of a circuit equals zero, and implies
that current adds in series.
(E) resistance in any loop of a circuit equals zero, and
implies that resistance adds in series.
15. A 100 W bulb and 60 W bulb are connected in series. The
voltage is greatest in the
(A) 100 W bulb
(C) It is the same for both.
(B) 60 W bulb
16. A 100 W bulb and 60 W bulb are connected in parallel. The
voltage is greatest in the
(A) 100 W bulb
(C) It is the same for both.
(B) 60 W bulb
17. A 100 W bulb and 60 W bulb are connected in series. The
current is greatest in the
(A) 100 W bulb
(C) It is the same for both.
(B) 60 W bulb
18. A 100 W bulb and 60 W bulb are connected in parallel. The
current is greatest in the
(A) 100 W bulb
(C) It is the same for both.
(B) 60 W bulb
19. As more lights are connected in series
(A) overall resistance increases.
(B) overall current flowing from the battery decreases and
the battery lasts longer.
(C) the electric potential of the power supply is unchanged.
(D) the lights become progressively dimmer.
(E) All of these.
20. As more lights are connected in parallel
(A) overall resistance decreases.
(B) overall current flowing from the battery increases and
the battery drains faster.
(C) the electric potential of the power supply is unchanged.
(D) the lights are at their brightest and do not change.
(E) All of these.
21. How are fuses and circuit breakers placed in circuits?
(A) Always in series.
(B) Always parallel.
(C) Series in DC circuits, parallel in AC circuits.
(D) Parallel in DC circuits, series in AC circuits.
(E) None of these.
1.
2.
3.
4.
5.
6.
E
H
A
E
B
A
7.
8.
9.
10.
11.
12.
A
D
C
D
B
B
13.
14.
15.
16.
17.
18.
A
B
A
C
C
A
22. Which is true for an ideal ammeter? It should have
(A) infinite resistance and be connected in series.
(B) infinite resistance and be connected in parallel.
(C) zero resistance and be connected in series.
(D) zero resistance and be connected in parallel.
(E) None of these is correct.
23. Which is true for an ideal voltmeter? It should have
(A) infinite resistance and be connected in series.
(B) infinite resistance and be connected in parallel.
(C) zero resistance and be connected in series.
(D) zero resistance and be connected in parallel.
(E) None of these is correct.
24. A capacitor is used to store
(A) charge.
(B) energy.
(C) potential.
(D) Both A and B.
(E) Both A and C.
25. Which answer will increase capacitance the most?
(A) Halve the plate area and halve the plate separation.
(B) Halve the plate area and double the plate separation.
(C) Double the plate area and halve the plate separation.
(D) Double the plate area and double the plate separation.
26. The energy stored in a capacitor is directly proportional to
(A) the voltage across the capacitor.
(B) the charge on the capacitor.
(C) the reciprocal of the charge on the capacitor.
(D) the square of the voltage across the capacitor.
(E) Both A and B.
27. If you double the distance between plates of a capacitor the
energy stored by the capacitor is
(A) ¼ its original value.
(D) doubled.
(B) ½ its original value.
(E) quadrupled.
(C) the same.
28. When two capacitors are connected in series, the total
capacitance is
(A) the sum of the individual capacitances.
(B) the sum of the reciprocals of each capacitor.
(C) larger than the individual capacitances.
(D) less than the capacitance of any of the individual
capacitors.
(E) More than one of the above answers is correct.
29. When two capacitors are connected in parallel, the total
capacitance is
(A) the sum of the individual capacitances.
(B) the sum of the reciprocals of each capacitor.
(C) larger than the individual capacitances.
(D) less than the capacitance of any of the individual
capacitors.
(E) More than one of the above answers is correct.
19.
20.
21.
22.
23.
24.
E
E
A
C
B
D
25.
26.
27.
28.
29.
C
E
D
D
E