Physics 113 Exam I Mock-up

18) Light of wavelength 550 nm in air is found to travel at 1.96 × 108 m/s in a certain liquid. (c = 3.0 × 108 m/s) (a) What is the index of refraction of this liquid? (b) What is the frequency of the light in air?

(a) 1.53 (b) 5.45 × 1014 Hz

54) A camera with a 20-cm diameter lens is recording images using a filter that allows only light of wavelength 600 nm to pass through. (a) What is the limit on the angular resolution (in microradians) in this case? (b) What is the diameter of the minimum-sized features that could be resolved on Mars with this camera? The distance to Mars at the time is 9.0 × 107 km.

(a) 3.7 μrad (b) 330 km

48) A slide projector needs to focus the image of a 24.0-mm x 36.0-mm slide onto a square screen 1.50 m on each side. You want to fill the screen as completely as possible without any of the image falling beyond the screen. Due to space constraints in the projector, the slide must be placed 10.5 cm from the lens. (a) What magnification does the projector produce? (b) How far from the lens should the screen be placed? (c) What focal length projector lens is needed?

(a) 41.7, (b) 4.38 m, (c) 10.3 cm

40) A 3.0-cm tall statue is 48 cm in front of a convex lens having a focal length of magnitude 20 cm. (a) Is the image of the statue real or virtual? (b) How far is the image from the lens? (c) Is the image upright or inverted? (d) How tall is the image?

(a) real (b) 34 cm (c) inverted (d) 2.1 cm

50) A nearsighted person has a far point of 50 cm for his right eye and 150 cm for his left eye. For each eye, what power contact lens will allow the person to see gorgeous sunsets?

-2.0 diopters (right eye), -0.67 diopters (left eye)

52) A compound microscope consists of an objective lens of focal length f0 and an eyepiece that by itself produces an angular magnification 25.0. The microscope is designed so that the object to be viewed is on the left side of the objective lens and is focused in a plane that is 28.00 cm away from the right-hand (or inside) focal point of the objective lens. When properly adjusted, the eyepiece and the objective lens are 29.90 cm apart. The eyepiece magnification is based on an image at infinity and a near point at 25.0 cm. What is f0?

0.90 cm

Even with perfect optics, what is the resolution limit (in radians) of the Hubble Space Telescope when it is focusing light of wavelength 400 nm? The mirror diameter is 2.4 m.

2.0 × 10-7 rad

49) For an eye that is 2.4 cm in diameter, what must be the range of focal lengths of the lens to focus objects from the near point (25 cm) to infinity on the retina?

2.2 cm ≤ f ≤ 2.4 cm

22) A diffraction grating is to be used to find the wavelength of the emission spectrum of a gas. The grating spacing is not known, but light of a known wavelength of 632.8 nm is deflected by 43.2° in the second order by this grating. Light of the wavelength to be measured is deflected by 34.9° in the second order. What is the wavelength of the light that is to be measured?

529 nm

37) A ray of light (ray a) in air strikes a flat piece of glass at an angle of φ0 = 84° with respect to the normal, as shown in the figure. The index of refraction of the glass is 1.5. What is the angle θ between the reflected ray (ray b) and refracted ray (ray c) rays? (SEE IMAGE)

54°

23) A soap bubble, when illuminated at normal incidence with light of 463 nm, appears to be especially reflective. If the index of refraction of the film is 1.35, what is the minimum thickness the soap film can be if it is surrounded by air?

85.7 nm

35) Which of the following terms describe lenses that are thicker at the center than at the edges? (There could be more than one correct choice.) A) converging lenses B) diverging lenses C) concave lenses D) convex lenses

A) converging lenses D) convex lenses

51) What is the focal length of the corrective contact lens needed by a nearsighted person whose far point is at 60 cm? A) -60 cm B) -30 cm C) +30 cm D) +60 cm E) +130 cm

A. -60 cm

41) A wrench is placed at 30 cm in front of a diverging lens with a focal length of magnitude 10 cm. What is the magnification of the wrench? A) 0.25 B) -0.25 C) 0.67 D) -0.67 E) 4.0

A. 0.25

19) Coherent light of wavelength 540 nm passes through a pair of thin slits that are 3.4 × 10^-5 m apart. At what angle away from the centerline does the second bright fringe occur? A) 1.8° B) 3.7° C) 4.3° D) 1.5° E) 5.0°

A. 1.8°

15) If a sheet containing a single slit is heated (without damaging it) and therefore expands, what happens to the angular location of the first-order diffraction minimum? A) It moves toward the centerline. B) It moves away from the centerline. C) It doesn't change.

A. It moves toward the centerline.

25) Light goes from material having a refractive index of n1 into a material with refractive index n2. If the refracted light is bent away from the normal, what can you conclude about the indices of refraction? A) n1 > n2 B) n1 ≥ n2 C) n1 < n2 D) n1 ≤ n2 E) n1 = n2

A. n1 > n2

13) Monochromatic coherent light shines through a pair of slits. If the wavelength of the light is decreased, which of the following statements are true of the resulting interference pattern? (There could be more than one correct choice.) A) The distance between the maxima stays the same. B) The distance between the maxima decreases. C) The distance between the minima stays the same. D) The distance between the minima increases. E) The distance between the minima decreases.

B) The distance between the maxima decreases. E) The distance between the minima decreases.

24) A 360-nm thick oil film floats on the surface of a pool of water. The indices of refraction of the oil and the water are 1.50 and 1.33, respectively. When the surface of the oil is illuminated from above at normal incidence with white light, what is the wavelength of light between 400 nm to 800 nm wavelength that is most weakly reflected? A) 520 nm B) 540 nm C) 560 nm D) 580 nm E) 600 nm

B. 540 nm

31) If a spherical concave mirror has a radius of curvature R, its focal length is A) R/4. B) R/2. C) R. D) 2R. E) 4R.

B. R/2.

43) Nearsightedness is usually corrected with A) converging lenses. B) diverging lenses. C) convex mirrors. D) cylindrical lenses. E) concave mirrors.

B. diverging lenses.

17) The colors on an oil slick are caused by reflection and A) diffraction. B) interference. C) refraction. D) polarization. E) ionization.

B. interference.

34) An upright object is 50 cm from a concave mirror of radius 60 cm. The character of the image is A) real and upright B) real and inverted C) virtual and upright D) virtual and inverted

B. real and inverted

20) Coherent light of wavelength 575 nm falls on a double-slit and the third-order bright fringe is seen at an angle of 6.5° away from the centerline. How far apart are the double slits? A) 5.0 μm B) 10 μm C) 15 μm D) 20 μm

C. 15 μm

12) If the index of refraction of a material is 2, this means that light travels A) 2 times as fast in air as it does in vacuum. B) 2 times as fast in the material as it does in air. C) 2 times as fast in vacuum as it does in the material. D) 2 times as fast in the material than it does in vacuum. E) 1/2 as fast in air as it does in the material.

C. 2 times as fast in vacuum as it does in the material.

47) Given perfect lenses, what is the main reason that a telescope with a large-diameter objective lens can produce a sharper image than one with a small-diameter lens? A) A larger lens can gather more light than a smaller lens B) A larger lens can focus more accurately than a smaller lens C) There is less diffraction with a larger lens than with a smaller lens D) A larger lens can focus more wavelengths of light than a smaller lens E) A larger lens has a longer focal length than a smaller lens

C. There is less diffraction with a larger lens than with a smaller lens

16) When a beam of light that is traveling in air is reflected by a glass surface, there is A) a 90° phase change in the reflected beam. B) no phase change in the reflected beam. C) a 180° phase change in the reflected beam. D) a 60° phase change in the reflected beam. E) a 45° phase change in the reflected beam.

C. a 180° phase change in the reflected beam.

46) A simple refracting telescope provides large magnification by employing A) a short focal length objective and a short focal length eyepiece. B) a short focal length objective and a long focal length eyepiece. C) a long focal length objective and a short focal length eyepiece. D) a long focal length objective and a long focal length eyepiece.

C. a long focal length objective and a short focal length eyepiece.

42) The focal length of the lens of a simple digital camera is 40 mm, and it is originally focused on a person 25 m away. In what direction must the lens be moved to change the focus of the camera to a person 4.0 m away? A) It does not make any difference. B) sideways from the CCD sensors C) away from the CCD sensors D) towards the CCD sensors

C. away from the CCD sensors

36) A convex lens has focal length f. If an object is located at "infinity" (very far away), the image formed is located at a distance from the lens A) of 2f. B) between f and 2f. C) of f. D) between the lens and f. E) of infinity.

C. of f.

27) Which one of the following sets of characteristics describes the image formed by a plane mirror? A) real and inverted B) real and upright C) virtual and upright D) virtual and inverted E) virtual and larger than the object

C. virtual and upright

26) A beam of light traveling in air strikes a glass slab at an angle of incidence less than 90°. After entering the glass slab, what does the beam of light do? (There could be more than one correct choice.) A) I follows the same path as before it struck the glass. B) It follows the normal to the glass slab. C) It bends away from the normal at the point of contact. D) It bends closer to the normal at the point of contact. E) It slows down.

D) It bends closer to the normal at the point of contact. E) It slows down.

29) Which one of the following numbers is the correct magnification produced by a plane mirror? A) 1/2 B) 1/4 C) 2 D) 1 E) 3/2

D. 1

21) A beam of light of wavelength 610 nm passes through a slit that is 1.90 μm wide. At what the angle away from the centerline does the second dark fringe occur? A) 11.4° B) 9.35° C) 12.2° D) 39.9° E) 18.7°

D. 39.9°

33) Single concave spherical mirrors produce images that A) are always smaller than the actual object. B) are always larger than the actual object. C) are always the same size as the actual object. D) could be smaller than, larger than, or the same size as the actual object, depending on the placement of the object. E) are always real.

D. could be smaller than, larger than, or the same size as the actual object, depending on the placement of the object.

14) In a double-slit interference experiment you are asked to use laser light of different wavelengths and determine the separation between adjacent maxima. You observe that this separation is greatest when you illuminate the double slit with A) blue light. B) green light. C) yellow light. D) red light. E) The separation is the same for all wavelengths.

D. red light.

30) A negative magnification for a mirror means that A) the image is inverted, and the mirror could be either concave or convex. B) the image is upright, and the mirror is convex. C) the image is inverted, and the mirror is convex. D) the image is inverted, and the mirror is concave. E) the image is upright, and the mirror could be either concave or convex.

D. the image is inverted, and the mirror is concave.

32) An object is placed in front of a convex mirror at a distance larger than twice the magnitude of the focal length of the mirror. The image will appear A) in front of the mirror. B) inverted and reduced. C) inverted and enlarged. D) upright and reduced. E) upright and enlarged.

D. upright and reduced.

39) An object that is 4.00 cm tall is placed 18.0 cm in front of a concave mirror having a focal length of 20.0 cm. What is the location of its image in relation to the mirror and what are its characteristics? A) 180 cm on the other side of mirror, real, 6.00 times bigger B) 10 cm on the other side of mirror, virtual, 10.0 times bigger C) 18 cm on the same side of mirror, virtual, 2.25 times bigger D) 20 cm on the same side of mirror, real, 10.0 times bigger E) 180 cm on the other side of mirror, virtual, 10.0 times bigger

E. 180 cm on the other side of mirror, virtual, 10.0 times bigger

38) A person jogs toward a plane mirror at a speed of 3 m/s. How fast is he approaching his image in the mirror? A) 1 5 m/s B) 3 m/s C) 4 m/s D) 5 m/s E) 6 m/s

E. 6 m/s

45) Which one of the following is a characteristic of a compound microscope? A) The objective is a diverging lens. B) The eyepiece is a diverging lens. C) The final image is real. D) The image formed by the objective is virtual. E) The image formed by the objective is real.

E. The image formed by the objective is real.

28) You may have seen ambulances on the street with the letters of the word AMBULANCE written on the front of them, in such a way as to appear correctly when viewed in your car's rear- view mirror. (See the figure.) How do the letters appear when you look directly at the ambulance (not through the mirror)? A) a B) b C) c D) d E) e (SEE IMAGE)

E. e

44) In a compound microscope A) both the objective and the eyepiece form real images. B) magnification is provided by the objective lens and not by the eyepiece. The eyepiece merely increases the resolution of the image viewed. C) magnification is provided by the objective and not by the eyepiece. The eyepiece merely increases the brightness of the image viewed. D) the magnification is m1 + M2, where m1 is the lateral magnification of the objective and M2 is the angular magnification of the eyepiece. E) the image of the objective serves as the object for the eyepiece.

E. the image of the objective serves as the object for the eyepiece.