PHYS2002 Practice Exam 3 (Ch. 25, 26, & 27)

Transcription

1 PHYS2002 Practice Exam 3 (h. 25, 26, & 27) onstants Name: m m q q p e o = 1.67 = 9.11 = = ε = 8.85 μ = 4π o p e c = m/s kg kg / N m T m/a 2 The Electromagnetic Spectrum Visible Spectrum Red Orange Yellow Green Blue Violet 700 nm 640 nm 575 nm 540 nm 480 nm 400 nm Wavelength 1

2 1. Santa laus looks at his reflection in a hristmas tree ornament (convex spherical mirror). Which one of the following statements concerning Santa's image is true? Ho, Ho, Ho... A) The image must be real. B) The image is farther from the ornament than Santa is. ) The image is larger than Santa. D) The image must be inverted. E) The image must be smaller than Santa. 2. My cat Socola walks directly toward a plane mirror at a speed of 0.25 m/s. What is the speed of his image relative to him. A) 0.13 m/s B) 0.25 m/s ) 0.50 m/s D) 0.75 m/s E) 1.0 m/s 3. What physical phenomenon is responsible for light changing direction at the interface between two different materials? A) Rarefaction B) Refraction ) ondensation D) Interference E) Diffraction 4. A ray of light from the left tries to pass thru three different materials. Each material has a different index of refraction. The figure is drawn to scale. Which of the following statements must be true? A) n 1 > n 2 B) n 1 < n 2 ) n 2 = n 3 D) n 1 = n 2 E) None of these. n 1 n 2 n 3 2

3 5. You are standing on the edge of a river bank when you see a fish swimming below the surface of the water. You decide to kill it with a spear. How must you throw the spear? A) Aim slightly above the image of the fish. B) Aim slightly below the image of the fish. ) Aim slightly to the right of the image of the fish. D) Aim slightly to the left of the image of the fish. E) Aim directly at the image of the fish. 6. Édouard Manet painted The Bar at the Folies Bergères shown below. In Manet s painting, the girl is standing in front of a large plane mirror that is parallel to the plane of the painting. Is her reflection consistent with the rules of geometrical optics? A) Yes B) No 7. Two mirrors are arranged as shown in the drawing. Light is incident on the first mirror at an angle of The light reflects toward a second mirror. Determine the angle θ. A) 20.0 o B) 25.0 o ) 15.0 o D) 30.0 o E).0 o 8. The radius of curvature of a spherical convex mirror is 52 cm. What is its focal length? A) 26 cm B) -26 cm ) 52 cm D) -52 cm E) 4 cm 3

4 9. A concave mirror in an amusement park has a radius of curvature of 4.0 m. A child stands in front of the mirror so that she appears 2.5 times taller than her actual height. If the image is upright, how far is she standing from the mirror? A) 1.2 m B) 3.5 m ) 2.8 m D) 4.0 m E) 7.0 m. A convex mirror has a radius of curvature of 0.50 m. Where must an object be placed in front of the mirror such that the image is formed 0.15 m behind the mirror? A) 0.38 m B) 0.19 m ) 0.77 m D) 0.09 m E) 0.57 m 11. A concave mirror is found to focus parallel rays at a distance of 9.0 cm. Where is the image formed when an object is placed 6.0 cm in front of the mirror? A) 11 cm in front of the mirror B) 18 cm behind the mirror ) 3.6 cm in front of the mirror D) 5.6 cm behind the mirror E) 9.2 cm in front of the mirror 12. An object is located between the center of curvature,, and the focal length, F, of a concave mirror as shown. At what location, denoted by the letters, will the image be formed? object F A B D E 4

5 13. A light ray is traveling in a diamond (n = 2.419). If the ray approaches the diamond-air interface, what is the minimum angle of incidence that will result in all of the light being reflected back into the diamond? The index of refraction for air is A) o B) o ) o D) o E) o 14. A converging lens is used to focus light from a small bulb onto a book. The lens has a focal length of.0 cm and is located 40.0 cm from the book. Determine the distance from the lens to the light bulb. A) 8.6 cm B) 13 cm ) 20 cm D) 30 cm E) 50 cm 15. A 2.00-cm tall object is placed 40.0 cm from a lens. The resulting image is 8.00 cm tall and upright relative to the object. Determine the focal length of the lens. A) 26.6 cm B) 32.0 cm ) 53.3 cm D) 64.0 cm E) 80.0 cm 16. In a Young's double slit experiment, light with a wavelength of 550 nm strikes a double slit with a slit separation distance of m. At what angle, relative to the central bright fringe, is the 3rd order dark fringe located? A) 12.7 o B) 14.8 o ) 8.4 o D).6 o E) None of these. 5

6 17. I have heard the following statement many times: The only manmade object on the surface of the Earth that is visible from outer space is the Great Wall of hina. Is this true??? In order to see the Wall, our eyes must be able to resolve both sides of the Wall. The maximum width of the Wall is 7.0 m. Let s assume that you are looking down at the Wall from space from a very low-earth orbit, an altitude of 200 km. The pupil diameter of your eye is 5.0 mm, and its average index of refraction is You are looking at the Wall with red light that has a wavelength in vacuum of 630 nm. Neglect the refractive effects of the Earth s atmosphere and calculate the smallest separation distance that you can resolve on the Earth s surface from this altitude. A) 30.7 m B) 22.6 m ) 0.03 m D) 41.8 m E) 5.89 m 18. The diffraction pattern from a single slit (width 0.02 mm) is viewed on a screen. The width of the central bright maximum is 2.6 cm. If light with a wavelength of 430 nm is used, what is the distance from the slit to the screen? A) 2.6 cm B) 5.2 cm ) 55.8 cm D) 60.4 cm E) None of these. 6

7 Answers 1. E B 4. A 5. B 6. B 7. A 8. B 9. A. A 11. B 12. A 13. A 14. B B 17. B, You can t see the Wall! 18. D 7