This exam consists of 27 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 105. The exam period was 90 minutes; the mean was 88.4; the median was 91. Click here to see page1 page2 of the formula sheet that came with the exam.

A concave spherical mirror of focal length 10 cm is used to observe distant objects.

At what distance from the mirror will the distant objects be focused?

(a) 5 cm (b) 10 cm (c) 20 cm

(a) upright, magnified. (b) upright, reduced. (c) inverted, magnified. (d) inverted, reduced. (e) upright, neither magnified nor reduced.

(a) The image would be larger and brighter. (b) The image would only be brighter. (c) The image would not change.

(a) It would increase in size. (b) It would decrease in size.

(a) 35.3° (b) 41.2° (c) 45.6° (d) 50.8° (e) 55.7°

(a) 0° - 90° (b) 45.6° - 90° (c) None of the above.

(a) 45.6° - 90° (b) 56.4° - 90° (c) None of the above.

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

A light ray is propagating within an optical fiber made from material with a high refractive index, n = 1.6, as shown in the figure. The fiber is surrounded by air, n_{air} = 1.

What is the maximum angle θ through which the optical fiber may be bent before the light ray will exit the fiber?

(a) 42.1° (b) 51.3° (c) 58.6°

(a) 33.8° (b) 44.3° (c) 50.9°

(a) 40.8° (b) 46.6° (c) 65.4°

An optical system consists of three parallel slabs, A, B, and C, in air, as shown in the figure. A ray of light that in vacuum has the wavelength 550 nm, is incident on the AB boundary, as shown. The refractive index of slab B is 2.4.

What is the wavelength of the light in slab B in nanometers?

(a) 550 (b) 447 (c) 352 (d) 229 (e) 195

(a) 1.1 (b) 1.4 (c) 1.7 (d) 2.7 (e) 2.9

(a) 1.0 (b) 1.3 (c) 1.4 (d) 1.7 (e) 2.1

A lens forms an image of an object which is 30 cm in front of the lens. The image is 6 cm from the lens on the same side of the object, as indicated in the figure.

What is the focal length of the lens in centimeters?

(a) -7.5 (b) -5.0 (c) +2.5 (d) +5.0 (e) +7.5

(T) True (F) False

(a) 2 (b) 5 (c) 6 (d) 10 (e) 15

(a) a = 5.0 × 10^{13} m (b) a = 2.5 × 10^{13} m (c) a = 1.22 × 10^{14} m (d) a = 1.49 × 10^{14} m (e) a = 2.75 × 10^{15} m

The total number of slits is greater in the pattern on the right than in the pattern on the left.

Reading glasses with a power of +2.0 diopters are used to help a far-sighted person see text as close as 35 cm in front of her eyes. Without the glasses, the closest she can see clearly is

(a) 0.66 m (b) 1.17 m (c) 1.53 m

(a) A (b) B

(a) 135 nm (b) 206 nm (c) 315 nm (d) 443 nm (e) 586 nm

(a) change. (b) not change.

Blue light with wavelength λ = 380 nm is incident upon two narrow slits separated by a distance d before striking a screen 5.2 meters away. The distance between the central bright fringe and first dark fringe is 1.8 × 10^{-3} m. Calculate d the spacing between the slits. (You may approximate sin(θ) ≈ tan(θ) ≈ θ.)

(a) d = 0.15 mm (b) d = 0.21 mm (c) d = 0.36 mm (d) d = 0.41 mm (e) d = 0.55 mm

(a) y < 1.8 mm (b) y = 1.8 mm (c) y > 1.8 mm