Light of Wavelength - Optics and Modern Physics - Past Paper, Exams of Physics

Download Light of Wavelength - Optics and Modern Physics - Past Paper and more Exams Physics in PDF only on Docsity! Physics 228 - Analytical Physics FIRST COMMON HOUR EXAM Thursday, Feb. 23, 2012 ! " SIGN HERE NOW: 1. The exam will last from 9:40 - 11:00 p.m. Use a #2 pencil to make entries on the answer sheet. Enter ID information items 2-5, now, on the answer sheet before the exam starts. 2. In the section labeled NAME (Last, First, M.I.) enter your last name, then fill in the empty circle for a blank, then enter your first name, another blank, and finally your middle initial. 3. Under STUDENT # enter your 9-digit RUID Number. 4. Enter 228 under COURSE; you may ignore the section number. 5. Under CODE enter the exam code from the label above. 6. During the exam, you may use pencils, a calculator, and one 8.5 x 11 inch sheet (both sides) with formulas and notes. 7. There are 16 multiple-choice questions on the exam. For each question, mark only one answer on the answer sheet. There is no deduction of points for an incorrect answer, so even if you cannot work out the answer to a question, you should make an educated guess. At the end of the exam, hand in the answer sheet and this SIGNED cover page. Retain the exam questions attached for future reference and study. 8. When you are asked to open the exam, make sure that your copy contains all 16 questions. Raise your hand if this is not the case, and a proctor will help you. Also raise your hand during the exam if you have a question. 9. Please have your student ID ready to show to the proctor during the exam. 10. Possibly useful information: the speed of light in vacuum is c = 3.0#108 m/s. 1. Which of the following is true? a) Light is a wave, not a particle. b) Light is a particle, not a wave. c) Light can be a particle or wave depending on how it is produced. d) High energy light like X-rays and !-rays are particles, but low energy light like radio waves and microwaves are waves. e) All light has particle and wave properties, independent of energy or production mechanism. 2. Some light of wavelength " = 600 nm in water (n = 1.333) passes from the water into air. What is its wavelength in air? a) 600 nm b) 450 nm c) 800 nm d) It depends on the angle of incidence with the water-air boundary. e) The light will not pass into the air, it will always be totally internally reflected and stay in the water. 3. A beam of light in water (to the left, n = 1.333) in a fish tank is incident on the glass wall (to the right, n = 1.54) of the tank at some angle. Which picture is qualitatively correct? a) b) c) d) e) 11. An object is 4 inches from a divergent lens whose focal length is 12 inches. What is the magnification of the image? a) 0.75 b) 3 c) -0.75 d) -3 e) 1.34 12. Light traveling in glass, with a refractive index of 1.6 is reflected at a glass- oil interface. The critical angle for total internal reflection is 60!. What is the index of refraction of the oil? a) 2 b) 0.9 c) 1.87 d) 1.38 e) 3 13. Plane monochromatic waves with wavelength 500 nm are incident normally on a plane transmission grating having 500 slits/mm. Find the angle of the m=2 interference maximum. a) 60! b) 45! c) 30! d) 20! e) 15! 14. In a two-slit interference pattern, the intensity at the peak of the central maximum is I0. At a point in the pattern where the phase di!erence between the waves from two slits is 60!, what is the intensity? (Neglect any e!ects from the widths of the individual slits.) a) 0.25I0 b) 0.50I0 c) 0.75I0 d) 0.87I0 e) I0 15. As shown, a picture of a person is placed facing a convergent lens, at a distance greater than the focal length of the lens. What does the image look like, viewed from beyond the image. (Further away from the lens.) a) b) c) d) e) 16. The woman in the drawing (thanks to Google Sketchup) is wondering why the mirror reverses her left/right, but not up/down. What would you tell her? a) It’s because your eyes are left / right, not up/down. b) It does reverse you up / down if you turn sideways. c) It doesn’t reverse you left / right or up/ down, it reverses you front / back. d) It does reverse you up / down too. e) Because the real world is three dimensional but the mirror is only two dimensional.