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 131. The exam period was 90 minutes; the mean score was 100.7; the median was 103. Click here to see page1 page2 page3 of the formula sheet that came with the exam.

Some helpful information: • 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}.

What smallest thickness t of oil would cause orange light (λ = 590 nm) to be most strongly reflected?

(a) 97 nm (b) 110 nm (c) 194 nm (d) 210 nm (e) 220 nm

A double-slit experiment is set up as shown in the figure below. Light from a laser illuminates a pair of slits etched in an opaque barrier. The spacing between the slits is 3 × 10^{-4} m; the distance from the barrier containing the slits to a viewing screen is 3 m. Because of diffraction, a pattern of light and dark spots is seen on the viewing screen. The distance from the central bright spot to the first bright spots on either side is 4 × 10^{-3} m.

What is the wavelength of the laser light illuminating the pair of slits?

(a) 200 nm (b) 400 nm (c) 500 nm (d) 1.22 × 10^{3} nm (e) 1.07 × 10^{4} nm

(a) increase by 100%. (b) increase by 50%. (c) remain unchanged. (d) decrease by 33%. (e) decrease by 50%.

A two-lens device is made from a convex lens with focal length f_{1} = 10 cm and a concave lens with focal length f_{2} = -20 cm as shown in the figure. A candle is placed 15 cm to the left of the convex lens. The image of the candle formed by the first lens serves as an object for the second lens which, in turn forms an image from this object. The lenses are 60 cm apart.

What is the position of the image formed by the concave lens?

(a) 45 cm to the right of the concave lens (b) 40 cm to the left of the concave lens (c) 20 cm to the left of the concave lens (d) 15 cm to the right of the concave lens (e) 12 cm to the left of the concave lens

(a) the candle's base is closer to the ceiling than is its flame -- the image is real. (b) the candle's base is closer to the ceiling than is its flame -- the image is virtual. (c) the candle's flame is closer to the ceiling than is its base -- the image is real. (d) the candle's flame is closer to the ceiling than is its base -- the image is virtual. (e) neither the flame nor the base is closer to the ceiling since the image is a point.

If there was complete constructive interference at X, what is a possible frequency of the light?

(a) 0 Hz (b) 0.25 Hz (c) 0.375 Hz (d) 4 × 10^{8} Hz (e) 1.2 × 10^{9} Hz

What is the final intensity of the light?

(a) 0.017 I_{0} (b) 0.033 I_{0} (c) 0.065 I_{0} (d) 0.188 I_{0} (e) 0.408 I_{0}

(a) 0° (b) 30° (c) 45° (d) 60° (e) 90°

A candle of height 5 cm is placed 4 cm away from a mirror. The image of the candle appears at a distance of 7 cm behind the mirror.

What kind of mirror is being used?

(a) flat (b) convex (c) concave

(a) -4 cm (b) -5.2 cm (c) 7.7 cm (d) 9.3 cm (e) 11.5 cm

(a) 2 cm (b) 3.4 cm (c) 5.5 cm (d) 6.9 cm (e) 8.8 cm

(T) True (F) False

(a) 1.06 × 10^{-4} V/m (b) 0.354 V/m (c) 120 V/m (d) 1.45 × 10^{2} V/m (e) 4.34 × 10^{3} V/m

An electromagnetic wave propagating in empty space is found to have a maximum electric field of 40 MV/m. What is the value of the maximum magnetic field to be found with this electric field?

(a) 1.2 × 10^{-3} T (b) 0.133 T (c) 40 T

In which phasor diagram is the instantaneous inductor voltage the greatest?

(a) (b) (c)

(a) less than the resonant frequency (b) equal to the resonant frequency (c) greater than the resonant frequency

If the voltage across the inductor is at a maximum, what is the voltage across the capacitor?

(a) -20.7 V (b) -9.2 V (c) -6.51 V (d) +9.2 V (e) +20.7 V

(a) 13.5 cm (b) 27 cm (c) 54 cm

(a) 0.37° (b) 0.93° (c) 22° (d) 60° (e) 67°

(a) 0 cm (b) 50 cm (c) 75 cm (d) 90 cm (e) 150 cm

(a) 1.33 (b) 1.29 (c) 1.25 (d) 1.19 (e) 1.08

What is the frequency of the tone if the speed of sound is 330 m/s?

(a) 2.6 kHz (b) 1.4 kHz (c) 1.0 kHz (d) 800 Hz (e) 50 Hz

(a) 7.91 V (b) 6.06 V (c) 3.21 V (d) 1.12 V (e) 0.761 V

An RLC circuit has R = 110 Ω, X_{L} = 200 Ω and X_{C} = 50 Ω, The circuit is supplied with 120 V (RMS) at 60 Hz.

What is the total impedance of the circuit?

(a) 102 Ω (b) 186 Ω (c) 224 Ω (d) 273 Ω (e) 305 Ω

(a) 0.53 H (b) 15 H (c) 75 kH

(a) 90 W (b) 156 W (c) 262 W