This exam consists of 29 questions; 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 130. When the exam was given, the mean was 96.7; the median was 100. Click here to see page1 page2 of the formula sheet that came with the exam.

Three particles of the same charge and the same speed of v, but with three different masses, enter a region of constant magnetic field into the page (B = 0.5 T)

Which particle has the largest mass?

(a) particle #1 (b) particle #2 (c) particle #3

(a) right (b) left (c) up (d) down (e) into the page

In region A, there exists a constant magnetic field (B = 2 T) pointing into the page. In region B, a constant magnetic field of unknown direction and magnitude exists. A charged particle of mass 3*10^{-20} Kg moves in an orbit in the plane of the paper as indicated by the arrowed curve. Since the magnetic field does not do any work, the particle’s speed remains constant and its speed is given by 10^{3} m/sec.

What is the direction of the magnetic field in region B?

(a) into the page (b) out of the page

(a) The magnetic field is stronger in region A than in region B. (b) The magnetic field is stronger in region B than in region A. (c) The magnetic field has the same magnitude in region A and B.

(a) 1.2 × 10^{-4} seconds (b) 9.1 × 10^{-5} seconds (c) 5.5 × 10^{-5} seconds (d) 2.0 × 10^{-5} seconds (e) 1.1 × 10^{-5} seconds

There is a wire carrying current out of the paper as shown by a thick circle with a dot in the middle. Concentric circles with arrows outside the wire represent the magnetic field lines. Which one of these diagrams describes the magnetic field lines the best?

(a) (b) (c) (d) (e)

(a) 0.80 amp (b) 1.6 amp (c) 4.7 amp (d) 5.0 amp (e) 8.2 amp

Three parallel wires carry identical currents (I_{1} = I_{2} = I_{3} = 3 A) in the same direction as shown.

What is the magnitude of the magnetic field at point x (1 meter away from wire #1 toward the other two wires)?

(a) 9.2 × 10^{-7} T (b) 7.5 × 10^{-7} T (c) 6.3 × 10^{-7} T (d) 4.5 × 10^{-7} T (e) 3.0 × 10^{-7} T

(a) up (b) down (c) into the paper (d) out of the paper (e) right

A square loop (0.5 meter sides) is placed in a constant magnetic field (B=5 T) as shown. An unknown current is flowing into and out of the paper as indicated by the x and the dot.

Due to the magnetic forces acting on the wire segments, a net torque will be generated. In which direction would the torque rotate the loop?

(a) clockwise (b) counter-clockwise

(a) 0.06 A (b) 0.16 A (c) 0.25 A (d) 0.37 A (e) 0.52 A

A circular conducting loop is being moved upward (toward the current-carrying wire) at a constant speed v. What will be the direction of the induced current?

(a) No current will be induced (no flux change). (b) Current will be induced clockwise. (c) Current will be induced counter-clockwise.

(a) zero. (b) always positive. (c) always negative. (d) first positive and then negative. (e) first negative and then positive.

A square, conducting loop of side length 1 cm is enclosed by a long solenoid with a larger diameter as shown. The solenoid is composed of a wire with 100 turns per cm and the current in the wire flows in the clockwise direction as shown. If the flux through the loop is 4*10^{-5} Weber, what is the current strength?

(a) 20.7 A (b) 31.8 A (c) 40.1 A

A square loop is enclosed by a long solenoid with a current flowing as shown by the arrow. Which configuration will give the largest magnetic flux?

A generator consists of a single square loop being rotated in a uniform magnetic field B = 0.25 tesla. The generator produces the following output V = 15 sin (38 t) volts. The picture shows the orientation of the loop at time t = 0.

Calculate the length L of a side of the rotating loop.

(a) L = 1.26 m (b) L = 1.75 m (c) L = 2.03 m

(a) to the left (b) up (c) in to the page

(a) 2.5 volts (b) 5.0 volts (c) 20 volts (d) 40 volts (e) 80 volts

Unpolarized light is incident on a series of two linear polarizers with transmission axis aligned 40° and 70° with respect to the vertical.

If the incident intensity is I_{0}, what is the intensity I_{2} transmitted by the stack?

(a) I_{2} = 0 (b) I_{2} = cos^{2}(40°) cos^{2}(70°) (c) I_{2} = cos^{2}(40°) cos^{2}(30°) (d) I_{2} = ˝ cos^{2}(40°) (e) I_{2} = ˝ cos^{2}(30°)

(a) never increase. (b) never decrease. (c) increase or decrease depending on the orientation of its transmission axis.

The RLC circuit below is being driven by an AC source resulting in a maximum current I_{max} = 0.25 amps.

Calculate V_{L} the maximum voltage across the inductor.

(a) V_{L} = 7 volts (b) V_{L} = 18 volts (c) V_{L} = 22 volts (d) V_{L} = 25 volts (e) V_{L} = 34 volts

(a) V_{0} = 12.5 volts (b) V_{0} = 13.9 volts (c) V_{0} = 15.3 volts (d) V_{0} = 18.4 volts (e) V_{0} = 21.8 volts

(a) 0 (b) 0.3 J/s (c) 1.6 J/s (d) 4.8 J/s (e) 8.3 J/s

(a) I reaches its maximum before E(t) reaches its maximum. (b) I reaches its maximum after E(t) reaches its maximum. (c) I reaches its maximum at the same time that E(t) reaches its maximum.

The figure to the right illustrates a plane electromagnetic wave. Compare the magnitudes of the x-component of the magnetic field at the points a and b.

(a) B_{a} > B_{b} (b) B_{a} = B_{b} (c) B_{a} < B_{b}

A local radio station broadcasts at the frequency 107.1 MHz (107.1 × 10^{6} Hz). At Loomis lab, the average energy density of this signal is 4 × 10^{-12} J/m^{3}.

What i s the wavelength l of this signal?

(a) l = 1.5 m (b) l = 2.3 m (c) l = 2.8 m

(a) 3.6 mJ (b) 6.0 mJ (c) 18 mJ

(a) 6.3 × 10^{-13} F (b) 1.1 × 10^{-12} F (c) 7.5 × 10^{-12} F (d) 4.4 × 10^{-11} F (e) 8.5 × 10^{-11} F