True-false questions are worth 2 points each, three-choice multiple choice questions are worth 3 points each, five-choice multiple choice questions are worth 6 points each. The maximum possible score is 115. The exam period was 90 minutes; the mean score was 85.9; the median was 87. Click here to see the formula sheet that came with the exam.

Some helpful information: • A physics 102 light bulb acts just like a resistor: its resistance is constant, independent of the current flowing through the light bulb. The bulb's brightness increases with increasing current. • A reminder about prefixes: p (pico) = 10^{-12}; n (nano) = 10^{-9}; μ (micro) = 10^{-6}; m (milli) = 10^{-3}; k (kilo) = 10^{+3}; M or Meg (mega) = 10^{+6}; G or Gig (giga) = 10^{+9}.

(T) True (F) False

(a) (b) (c)

A network of capacitors is shown in the figure below. All capacitors are identical, with capacitance C = 3 μF. A battery maintains a potential difference of 2V across the network. Two of the 3 μF capacitors have been labeled, for identification in the problems.

What is the equivalent capacitance of the network?

(a) C_{eq} = 1.8 μF (b) C_{eq} = 2.4 μF (c) C_{eq} = 3.6 μF (d) C_{eq} = 4.8 μF (e) C_{eq} = 6.0 μF

(a) Q_{1} = Q_{2} (b) Q_{1} > Q_{2} (c) Q_{1} < Q_{2}

(a) Q_{1} increases. (b) Q_{1} decreases. (c) Q_{1} remains the same.

(a) 7.38 V (b) 14.22 V (c) 17.78 V (d) 21.33 V (e) 24.62 V

(a) 3 V (b) 7 V (c) 15 V

The capacitor is initially uncharged. At time t_{1} the switch is closed; at t_{2} the switch is opened. The time interval t_{2} - t_{1} is roughly the same size as RC for this circuit. Which graph best represents the current I flowing in the circuit?

(a) graph A (b) graph B (c) graph C (d) graph D (e) graph E

The illustrated circuit contains a battery, a 75 watt bulb, and a 25 watt bulb. (The bulbs consume the specified power when connected to a 100 V battery.)

Which one of the following statements is correct?

(a) The 75 watt bulb has larger resistance than the 25 watt bulb. (b) The 75 watt bulb has smaller resistance than the 25 watt bulb. (c) The resistances of both bulbs are the same.

(a) 100 Ω (b) 75 Ω (c) 50 Ω (d) 25 Ω (e) 15 Ω

(a) 0 J (b) -0.0255 J (c) +0.0975 J (d) +0.036 J (e) +0.108 J

What is the difference in the electric potential at points A and B, namely V(B) - V(A)?

(a) 0 V (b) +9000 V (c) +48000 V (d) -9000 V (e) -48000 V

A point charge of -2 μC is placed 1 m to the right of a neutral conducting sphere of radius 0.25 m.(Note that only one of the figures (a), (b), (c) is correct.)

Which one of the charge distributions shown in the figure best describes the charge distribution on the surface of the conductor?

(a) zero. (b) attractive. (c) repulsive.

(a) positive. (b) zero. (c) negative.

(a) 2 A. (b) 8 A. (c) 15 A.

The current I is

(a) 5 A (b) 15 A (c) 60 A

At what time does the capacitor volatage V_{C} reach 90% of the battery voltage V_{battery}?

(a) 0.10 × RC (b) 0.31 × RC (c) 2.30 × RC (d) 2.72 × RC (e) 10.0 × RC

(a) 0.93 A (b) 4.01 A (c) 1.76 A (d) 2.87 A (e) 1.56 A

(a) C_{1} > C_{2} (b) C_{1} = C_{2} (c) C_{1} < C_{2}

(a) 20 Ω (b) 12 Ω (c) 6 Ω (d) 4 Ω (e) 3 Ω

Two charges of +2 μC and -2 μC are separated by a distance of 1 m. The point P is equidistant to the two charges and 0.5 m above the line joining the charges, as shown in the figure below.

What is the magnitude of the force on a +10 μC charge placed at point P?

(a) 0.0 N (b) 0.127 N (c) 0.509 N (d) 1.2 N (e) 0.254 N

(a) to the right (b) to the left (c) up

(a) It remains the same. (b) It becomes twice as large. (c) It becomes four times larger.

(a) -0.036 J (b) 0.072 J (c) 0 J (d) 0.144 J (e) -0.0191 J