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 99. The exam period was 90 minutes; the average score was 85.2; the median score was 88. Click here to see page1 page2 of the formula sheet that came with the exam.

The switch is initially open and the capacitor initially carries a charge Q_{0} = +10 μC on the top plate and -Q_{0} on the bottom plate. At t = 0 the switch is closed.

What is the maximum current I_{max} in this LC circuit? (Note: 1 mA = 10^{-3} A)

(a) I_{max} = 1 mA (b) I_{max} = 5 mA (c) I_{max} = 8 mA (d) I_{max} = 10 mA (e) I_{max} = 12 mA

(a) t_{1} = 6.15 ms (b) t_{1} = 12.57 ms (c) t_{1} = 9.36 ms (d) t_{1} = 3.14 ms (e) t_{1} = 1.48 ms

(a) dI / dt = 1.3 A/s (b) dI / dt = 2.0 A/s (c) dI / dt = 5.0 A/s

The current as a function of time is shown in the right- hand side figure.

Which one of the following graphs best describes the voltage across the inductor V_{L}(t) = V_{B} - V_{A} as a function of time?

(a) (b) (c)

(a) increases. (b) remains the same. (c) decreases.

At what frequency f = ω / 2π is I_{rms} maximum?

(a) 0 Hz (b) 3.55 × 10^{-5} Hz (c) 712 Hz (d) 4.47 × 10^{3} Hz (e) 3.18 × 10^{6} Hz

(a) leads. (b) lags. (c) is in phase with.

(T) True (F) False

(a) ω > ω_{o} (b) ω < ω_{o} (c) ω = ω_{o}

What is the rms power provided to the circuit?

(a) <P(t)> = 330 W (b) <P(t)> = 450 W (c) <P(t)> = 570 W (d) <P(t)> = 621 W (e) <P(t)> = 660 W

(a) E_{0} = 27.5 V/m and B_{0} = 9.2 × 10^{-8 } T (b) E_{0} = 1 V/m and B_{0} = 3 × 10^{-9 } T (c) E_{0} = 1 V/m and B_{0} = 1 T (d) E_{0} = 13.7 V/m and B_{0} = 17.6 T (e) E_{0} = 34.3 V/m and B_{0} = 1.1 × 10^{-7} T

The primary coil of an ideal transformer is connected to an AC voltage source as shown in the figure below. There are 100 turns in the primary coil and 20 turns in the secondary coil.

If the voltage drop measured across the resistor is V_{2} = 50 V, what is the voltage provided by the AC generator?

(a) V_{1} = 10 V (b) V_{1} = 50 V (c) V_{1} = 250 V

(a) 1.2 (b) 2 (c) 10

A beam of light, initially polarized along the y-axis, passes through a linear polarizer and then through a quarter wave plate, aligned as shown in the diagram.

What is the polarization state of the light that emerges from the quarter wave plate?

(a) circularly polarized (b) linearly polarized at 45° (c) linearly polarized at -45°

(a) I_{2} = 0 (b) I_{2} = I (c) I_{2} = I / 2 (d) I_{2} = I / 4 (e) I_{2} = I / √2

A plane electromagnetic wave propagates in vacuum. The figure below represents a snapshot at time t = 0 of the electric field associated with this wave, which is described by E = E_{0} sin(ωt-kx) y with E_{0} = 1000 V/m. The frequency is f = 300 kHz. Points P and Q are along the x-axis.

Which one of the following options correctly relates B_{P}, the magnitude of the magnetic field at point P at time t = 0, to B_{Q}, the magnitude of the magnetic field at point Q at time t = 0?

(a) B_{P} = B_{Q} = 0 (b) B_{P} > B_{Q} = 0 (c) B_{P} = B_{Q} > 0

(a) +x (b) -x (c) +y

(a) 2 (b) 1/2 (c) 4

(a) λ = 0.1 m (b) λ = 1.0 m (c) λ = 100 m (d) λ = 1000 m (e) λ = 10000 m

A beam of unpolarized light of intensity I_{0} travels in the +z-direction and goes through an arrangement of three linear polarizers as shown in the figure below. The planes of all polarizers are parallel to the xy plane.

Find the ratio between the final intensity I_{f} and initial intensity I_{0}.

(a) I_{f} / I_{0} = 0.16 (b) I_{f} / I_{0} = 0.28 (c) I_{f} / I_{0} = 0.38 (d) I_{f} / I_{0} = 0.42 (e) I_{f} / I_{0} = 0.75

(a) increase. (b) remain the same. (c) decrease.

(a) 9 μJ (b) 16 μJ (c) 18 μJ (d) 25 μJ (e) 32 μJ

A person is driving in such a way that a red (600 nm) light appears to be green (500 nm).

How fast is the person driving?

(a) 2.7 × 10^{7} m/s (b) 5.4 × 10^{7} m/s (c) 1.6 × 10^{9} m/s

(a) toward the light. (b) away from the light.