Download Curved Part of Lens - Optics and Modern Physics - Past Paper and more Exams Physics in PDF only on Docsity! Physics 228– Exam I February 21, 2008 Profs. Coleman and Andrei Your name sticker with exam code ⇒ SIGNATURE: 1. The exam will last from 9:40 p.m. to 11:20 p.m. Use a #2 pen- cil to make entries on the answer sheet. Enter the following ID information now, before the exam starts. 2. In the section labelled 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 Identification Number. 4. Enter 228 under COURSE, and your section number (see label above) under SEC. 5. Under CODE enter the exam code given above. 6. During the exam, you may use pencils, a calculator, and one handwritten 8.5 x 11 inch sheet with formulas and notes, with- out attachments. 7. There are 15 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 the cover page. Retain this question paper for future reference and study. 8. When you are asked to open the exam, make sure that your copy contains all 15 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 SIGN the cover sheet under your name sticker. A proctor will check your name sticker and your student ID some- time during the exam. Please have them ready. 10. Good luck! Useful Information speed of light: c = 3.00 × 108 m/s 1 nm = 10−9 m 1 1. A spherical mirror forms an image that is virtual, one-quarter of the size of the object, and is 3 cm from the mirror. What is the focal length of the mirror? a) +2.4 cm b) −0.25 cm c) +1.0 cm d) +0.6 cm e) −4.0 cm 2. X-rays of wavelength 0.129 nm are incident on a crystal, and a first-order maximum is observed at an angle of 8.15◦ to the plane of atoms. What is the interplanar spacing? a) About 0.40 nm b) About 0.35 nm c) About 0.25 nm d) About 0.30 nm e) About 0.45 nm 3. The tank shown in the figure holds a layer of oil, 1.88 m thick, which floats on a layer of syrup that is 0.69 m thick. Both liquids are clear and do not intermix. A ray, which originates at the bot- tom of the tank on a vertical axis, crosses the oil-syrup interface at a point 0.90 m from the axis. The ray continues and arrives at the oil-air interface, 2.00 m from the axis and at the critical angle.The index of refraction of the oil is closest to: a) 2.00 b) 1.98 c) 2.02 d) 1.96 e) 1.94 4. The radius of the curved part of lens L3 in the figure is 35.0 cm, and the refractive index of the lens material is 1.62. The focal length of L3 is closest to: a) +21.6 cm b) +56.5 cm c) -21.6 cm d) -56.5 cm e) +28.2 cm 5. Coherent monochromatic light of wavelength 625 nm passes through a pair of thin parallel slits whose spacing is 2.81×10−6m. At most, how many bright fringes can be formed on one side of the central bright fringe (not counting the central bright fringe)? a) 2 b) 3 c) 4 d) 5 e) 6 6. A single slit forms a diffraction pattern, with the first minimum at an angle of 40◦ from central maximum. Monochromatic light of wavelength 640-nm is used. The width of the slit, in nm, is closest to: a) 996 b) 955 c) 873 d) 832 e) 914 1
