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 122.
The exam period was 90 minutes; the mean was 102.6; the median was 104.
Click here to see page1
page2 of the formula sheet that came
with the exam.
(a) n1 > n2
(b) n1 < n2
(c) The speed of light in medium 2 is greater than in medium 1.
For this figure, if the angle of incidence in medium 1 is 30°,
what is the angle α3 (with respect to the surface
normal) of the light inside medium 3?
Assume now that the prism is replaced with another one of the same
shape but with an index of refraction n = 1.663. With respect to the
original prism, the emerging angle is
(a) 25 cm
(b) 12.5 cm
(c) 6.25 cm
(d) 3.125 cm
(e) 50 cm
A concave mirror has a radius of curvature of 5 m. The object is
initially placed at 2 m from the mirror (position A) . Then the object
is moved to Position B (6 m away from the mirror). Is the size of the
image of the object when it is placed at 6 m from the mirror larger,
smaller or equal to the size of the image of the same object when it was
placed at 2 m from the mirror?
(a) M = -1
(b) M = -2
(c) M = 2.5
(d) M = 10
(e) M = 5
White light passes through the prism and comes out as shown below.
Which one of the statements below is wrong?
(a) Red light gets deflected less than blue light.
(b) The refractive index index is greater for red light than for blue light.
(c) The refractive index of the prism depends on the wavelength of light.
(d) The refractive index in vacuum is independent of the wavelength of light.
(e) No dispersion will occur if the refractive index of the prism does not depend on the wavelength of light.
A fiber optic line can transport light over long distances
by using total internal reflection to reflect the light back into the fiber.
The fiber shown has a core (n = 1.67) surrounded by a material of a different
index (n = 1.33).
Inside the fiber, what is the maximum angle θcapture
the light can have and still undergo total internal reflection?
(a) θcapture = 31.8°
(b) θcapture = 37.2°
(c) θcapture = 43.4°
(d) θcapture = 48.7°
(e) θcapture = 54.3°
(a) θcapture will increase.
(b) θcapture will decrease.
(c) Total internal reflection will no longer be possible for light traveling through the core of the fiber.
Two lenses are separated by 18 cm. Lens #1 is convergent and has a
focal length of 5 cm Lens #2 is divergent and has a focal length of -7
cm. An object (arrow) is located 10 cm to the left of Lens #1.
If lens #2 were not present, the image formed by
lens #1 would be
(a) inverted relative to the object.
(b) upright relative to the object.
(a) to the left of lens #2 and more than 7 cm away from lens #2
(b) to the right of lens #2 and more than 7 cm away from lens #2
(c) to the left of lens #2 and less than 7cm away from lens #2
(d) to the right of lens #2 and less than 7cm away from lens #2
(a) shorter than the object.
(b) larger than object.
(c) the same height as the object
A farsighted student cannot see objects closer than 50 cm from his
eyes. To correct his vision, he would need to see objects as close as
25 cm from his eyes (so that the lens should form a
virtual image at 25 cm of an object at 50 cm).
What type of correction lens should he wear?
(a) 50 cm
(b) 40 cm
(c) 30 cm
(d) 20 cm
(e) 10 cm
(a) m = 0.667
(b) m = 1.5
(c) m= 1
(d) m = -1.5
(e) m = -0.667
Later, a thick block of plastic with index of refraction n =
1.50 is placed between the diffraction grating and the screen, entirely
filling the gap between the grating and the screen. After this is done,
the separation between the bright spots on the screen is:
(a) 0.67 cm
(b) 1.00 cm
(c) 1.50 cm
Which device has the larger number of slits?
(a) device a
(b) device b
Later, the second speaker is attached to the signal generator so that
both speakers are driven in phase by the same signal. (The signal
generator produces twice as much current in order to drive both speakers
with the same amplitudes as the single speaker had been driven
previously.) As the listener wanders through the same regions, he/she
finds that the sound is
(a) sometimes louder, sometimes softer than before.
(b) always louder than before.
(c) the same as before.
A double-slit experiment is set up as shown in the following figure.
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
(a) 2.00 × 10-6 nm
(b) 400 nm
(c) 500 nm
(d) 1.22 × 105 nm
(e) 107 nm
(a) increase by 100%.
(b) increase by 50%.
(c) remain unchanged.
(d) decrease by 30%.
(e) decrease by 50%.
Stray light of wavelength λ = 560 nm is normally incident
on the lens. In order to minimize reflections from the back of the
lens, the thickness of the coating should be:
(a) t = 1120 nm
(b) t = 560 nm
(c) t = 280 nm
(d) t = 108 nm
(e) t = 1.22 nm
Which one of the following statements can be correct?
Relative to the center of the bright spot, which is white,
(a) point A contains equal intensities of all colors of light while point B
consists only of red light.
(b) point A contains only blue light while point B contains only red light.
(c) points A and B only contain green light.
(d) point A is deficient in blue light while point B is deficient in red
(e) point A is deficient in red light while point B is deficient in blue
A binary star system is 1018 meters (approximately 100
lightyears) from Earth. The two stars in the system move in circular
orbits and remain a distance D apart. An earth-based telescope
whose aperture is 2m observes light coming from the stars.
Assume that the starlight seen by the telescope has wavelength 500
× 10-9 m. What is the minimum distance D between
the stars that will allow the telescope to resolve the binary system as
comprising two well-separated stars?
(a) 2.50 × 10-7 m
(b) 3.00 × 108 m
(c) 3.05 × 1011 m
(d) 5.00 × 1011 m
(e) 5.00 × 1020 m
(a) D decreases by 20%
(b) D remains unchanged
(c) D increases by 20%