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 116.
The exam period was 90 minutes; the mean score was 94.2; the median was
98. Click here to see page1
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.
An optical fiber consists of a small cylinder of glass called the core,
shown in gray, surrounded by a layer of glass called the cladding.
Light rays entering the fiber propagate as shown. The index of
refraction of the core is n = 1.444 . The intensity of the light
in the fiber is 1.3 × 108 W/m2.
If the maximum angle off-axis θ with which a ray can
propagate in the fiber is 4°, what is the index of refraction of the
(a) 10 mW
(b) 40 mW
(c) 62 mW
(a) 1.2 × 108 m/s
(b) 2.1 × 108 m/s
(c) 4.3 × 108 m/s
(a) half the height
(b) ¾ of the height
(c) same height
(d) slightly longer than the height
(e) twice the height
(a) -20 diopters
(b) -5 diopters
(c) 0.05 diopters
(d) 5 diopters
(e) 20 diopters
Two lenses are indicated below. The convex lens has a focal length
of 11 cm and the concave lens has a focal length of -17 cm. The object
is located 14.1 cm to the left of the convex lens.
Where is the final image located with respect to the concave lens?
Standard sign conventions apply.
(a) -10.1 cm
(b) 24.3 cm
(c) 32.0 cm
(d) 44.9 cm
(e) 60.4 cm
A sodium light bulb is analyzed with a diffraction grating. The
slits of the grating have a separation of 1000 nm. The sodium light has
two closely spaced emission lines, whose wavelengths are 589.0 nm and
What is the angle Δθ between the first-order
maxima corresponding to 589.0 nm and the first-order maxima of 589.6
(c) There is no second-order maximum.
A vertically polarized beam of light goes through a system of 5
polarizers. The first polarizer is oriented at 18° from the
vertical, and the transmission axis of each successive polarizer is
oriented 18° from the previous one.
The emerging beam from the five polarizers has an intensity of 30
W/m2. What is the intensity of the incident light?
(a) 24.78 W/m2
(b) 38.56 W/m2
(c) 49.55 W/m2
(a) 0.3 J
(b) 1.8 J
(c) 18 J
(d) 29.7 J
(e) 180000 J
A series RLC circuit is driven by a generator with voltage
V(t) = 10 sin(100t) volts. At some instant
t0, the voltage of the generator was observed to be at
its maximum (positive) value. Which one of the following could
correctly represent the phasor diagram of this circuit at this instant
(a) Paverage = 2.72 watts
(b) Paverage = 3.14 watts
(c) Paverage = 5.11 watts
(d) Paverage = 10.5 watts
(e) Paverage = 25.0 watts
What is I1 after sending unpolarized light
with intensity I0 through the same system of
polarizers but in the opposite direction (from right to left)?
(a) ¼ I0
(b) ½ I0
(a) 1.73 nT
(b) 2.54 nT
(c) 6.47 nT
(d) 15.5 nT
(e) 35.4 nT
A radio wave (1 MHz) is transmitted around town from a nearby tower.
The electromagnetic wave can be represented by the following picture.
What is the wavelength of the signal?
(a) 100 m
(b) 150 m
(c) 200 m
(d) 300 m
(e) not enough information
(a) in the +x direction
(b) in the +z direction
(c) in the -y direction
(a) x direction
(b) y direction
(c) z direction
(a) 1.0 × 10-9 T
(b) 2.3 × 10-7 T
(c) 5.0 × 10-6 T
Consider an object 2 cm in height placed 15 cm in front of a concave
mirror of focal length f = 5 cm, as shown in this figure.
Which one of the rays in the picture is incorrect?
(a) ray 1
(b) ray 2
(c) ray 3
(a) Only the top half of the object is imaged.
(b) Only the bottom half of the object is imaged.
(c) The whole object is imaged, but the image is dimmer.
What is the angle α ?
An argon-ion laser produces visible light of wavelength
λ = 514 nm in air which strikes the top
surface of the upper film. The incident light ray is actually
vertical. The thickness of the material with index
n2 is d.
Which minimum value of d can produce a bright reflected
(a) d = 10 nm
(b) d = 34 nm
(c) d = 69 nm
(d) d = 137 nm
(e) d = 215 nm