Phy 102 Homework Solutions 2007

Phy 102 Homework Solutions 2007 - ashkenazi Professor...

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Unformatted text preview: ashkenazi Professor Josef Ashkenazi Contact Information University of Miami, Department of Physics James L. Knight Physics Building, Room 310 Post Office Box 248046 Coral Gables, FL 33124 Telephone: (305) 284-2323 ex.3 Fax: (305) 284-4222 Associate Professor; Ph.D., Hebrew University of Jerusalem, 1975 Office Hours: Wednesday and Friday 10:00-10:30 am [email protected] UM Physics Home Page UM Schedule 2006-07 Phy102 Class Record (requires password) Phy102 Homework #1 Phy102 Homework #2 Phy102 Homework #3 Phy102 Homework #4 Phy102 Homework #5 Practice Test #1: p. 1, p. 2, p. 3, p. 4, p. 5, p. 6 Phy102 Homework #6 Phy102 Homework #7 Phy102 Homework #8 Phy102 Homework #9 Phy102 Homework #10 Practice Test #2: p. 1, p. 2, p. 3, p. 4, p. 5 Phy102 Homework #11 Phy102 Homework #12 Practice Final Test: 1, 2, 3, 4, 5, 6, 7 Ashkenazi's Home Page Physics Classes Summer 2007 Phy102 Syllabus Solution of HW#1 Solution of HW#2 Solution of HW#3 Solution of HW#4 Solution of HW#5 Solution Test #1 Solution of HW#6 Solution of HW#7 Solution of HW#8 Solution of HW#9 Solution of HW#10 Solution Test #2 Solution of HW#11 Solution of HW#12 Solution Final Test P Instructions Concerning Exams http://www.physics.miami.edu/ashkenazi/102_sum/ [7/31/2007 8:51:11 AM] Request to View Grades Request to View Grades Please enter the information indicated in order to view your complete grade records for physics 102. Your ID number is the UM one that looks like C07654321. When you FIRST use the system your password will be constructed from the last four digits of this ID number and the first two letters of your last (family) name. You MUST THEN change this password to some other one of your choice. It will be held in an encrypted file, so please pick something that you can remember. ID number: Password: Display Grades Clear If you wish to change your password, enter the information here. 6 to 28 characters; case doesn't count but spaces do. ID number: Password: New Password: Enter New Password Again: Implement Password Change Clear http://www.physics.miami.edu/ashkenazi/102_sum/display_grades.html [7/31/2007 8:51:12 AM] PHYSICS 102 A --- SUMMER 1 2007 PHYSICS 102 A - SUMMER 1 2007 COURSE CALENDAR APPROXIMATE SYLLABUS Prof. J. Ashkenazi DAY LECTURE TOPIC(S) May 24 May 25 Electric Charges, Forces, & Fields Electric Charges, Forces, & Fields Electric Potential & Potential Energy Electric Potential & Potential Energy Electric Current & DC Circuits Electric Current & DC Circuits Magnetism Magnetism May 28 Memorial Day CHAPTER May 16 May 17 May 18 May 21 May 22 May 23 May 29 May 30 May 31 19 20 20 21 21 22 22 No classes Faraday's Law of Induction Alternating Current Electromagnetic Waves June 1 June 4 June 5 June 6 19 23 24 25 TEST I Electromagnetic Waves Geometrical Optics Optical Instruments http://www.physics.miami.edu/ashkenazi/102_sum/syl.htm (1 of 2) [7/31/2007 8:51:12 AM] 19-24 25 26 27 PHYSICS 102 A --- SUMMER 1 2007 June 7 June 8 June 11 June 12 June 13 June 14 Physical Optics: Interference & Diffraction Physical Optics: Interference & Diffraction Relativity Quantum Physics Quantum Physics Atomic Physics June 15 June 18 June 19 June 20 June 21 28 28 29 30 30 31 TEST II Atomic Physics Nuclear Physics & Radiation Nuclear Physics & Radiation Reading Day June 22 25-30 31 32 32 No classes Final Exam 19-32 Chapter references are to Physics by James S. Walker, Second Edition (Prentice Hall, 2004, 2002). The final exam will count as two tests. There will be homework assignments and quizzes, and their grades will be averaged, dropping the lowest score of each. The averaged homework and quiz grades will count together as one test, where 40% of its grade is determined by the homework assignments, and 60% by the quizzes. The lowest of the five scores (counting 25% equally) will be dropped. Attendance may affect your final grade. Students are responsible for signing the attendance sheet when it is circulated. File translated from TEX by TTH, version 3.40. On 14 May 2007, 14:55. http://www.physics.miami.edu/ashkenazi/102_sum/syl.htm (2 of 2) [7/31/2007 8:51:12 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #1 Prof. J. Ashkenazi Chapter 19 Suggested Problems: 1, 9, 13, 15, 17, 21, 25, 33, 35, 42, 43, 46, 53, 55 Problems to be submitted on May 18, 2007: 12, 16, 20, 24, 34, 38, 48, 54 File translated from TEX by TTH, version 3.40. On 14 May 2007, 14:55. http://www.physics.miami.edu/ashkenazi/102_sum/hw1.htm [7/31/2007 8:51:13 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #2 Prof. J. Ashkenazi Chapter 20 Suggested Problems: 1, 11, 13, 17, 23, 25, 31, 33, 35, 39, 41, 43, 51, 53, 55, 60 Problems to be submitted on May 22, 2007: 10, 20, 26, 32, 38, 44, 50, 56, 58 File translated from TEX by TTH, version 3.40. On 22 May 2007, 15:57. http://www.physics.miami.edu/ashkenazi/102_sum/hw2.htm [7/31/2007 8:51:14 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #3 Prof. J. Ashkenazi Chapter 21 Suggested Problems: 1, 3, 7, 9, 11, 13, 15, 17, 19, 23, 25, 27, 29, 33, 37, 38, 39, 46, 49, 51, 53, 55, 60, 61, 63, 65 Problems to be submitted on May 25, 2007: 6, 14, 24, 32, 34, 42, 50, 52, 58, 66 File translated from TEX by TTH, version 3.40. On 21 May 2007, 11:28. http://www.physics.miami.edu/ashkenazi/102_sum/hw3.htm [7/31/2007 8:51:15 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #4 Prof. J. Ashkenazi Chapter 22 Suggested Problems: 1, 7, 9, 13, 15, 17, 19, 23, 27, 29, 30, 33, 34, 39, 41, 43, 49, 51 Problems to be submitted on May 29, 2007: 8, 10, 18, 20, 28, 36, 46, 50 File translated from TEX by TTH, version 3.40. On 23 May 2007, 11:21. http://www.physics.miami.edu/ashkenazi/102_sum/hw4.htm [7/31/2007 8:51:16 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #5 Prof. J. Ashkenazi Chapter 23 Suggested Problems: 3, 7, 9, 15, 16, 19, 22, 23, 26, 27, 29, 30, 31, 35, 37, 39, 43, 44, 45, 47, 50, 51, 55, 57, 61 Problems to be submitted on May 31, 2007: 6, 14, 24, 32, 38, 42, 46, 52, 60 Chapter 24 Suggested Problems: 1, 3 Problems to be submitted on May 31, 2007: 6 File translated from TEX by TTH, version 3.40. On 25 May 2007, 10:59. http://www.physics.miami.edu/ashkenazi/102_sum/hw5.htm [7/31/2007 8:51:17 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt11.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt11.jpg (1 of 2) [7/31/2007 8:51:19 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt11.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt11.jpg (2 of 2) [7/31/2007 8:51:19 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt12.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt12.jpg (1 of 2) [7/31/2007 8:51:21 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt12.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt12.jpg (2 of 2) [7/31/2007 8:51:21 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt13.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt13.jpg (1 of 2) [7/31/2007 8:51:23 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt13.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt13.jpg (2 of 2) [7/31/2007 8:51:23 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt14.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt14.jpg (1 of 2) [7/31/2007 8:51:25 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt14.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt14.jpg (2 of 2) [7/31/2007 8:51:25 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt15.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt15.jpg (1 of 2) [7/31/2007 8:51:28 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt15.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt15.jpg (2 of 2) [7/31/2007 8:51:28 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt16.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt16.jpg (1 of 2) [7/31/2007 8:51:29 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt16.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt16.jpg (2 of 2) [7/31/2007 8:51:29 AM] Physics 102 [l] Two coins carry identical charges. These two coins are lying 3.00 m apart on a table. If each of these coins experiences a force of 2.00 N, how large is the charge on each coin? [A] 2.24 pC [B] 4.47 pC [C] 8.71 pC [D] 22.4 pC (JE})44.7 pC [2] The figure shows four Gaussian surfaces surrounding a distribution of charges. The Gaussian surface (surfaces) that has (have) no electric flux through it (them) is (are) [ A ]a ' . ^ '; ; ^2i^-i.« •.. /' /, D] d [E] b and d [3] A charged particle with charge +5.0 /xC is initially at rest. It is accelerated through a potential difference of 500 V. What is the k inetic energy of this charged particle? [A] 2.5 x 10~3 J/m (Sj2.5 x 10~3 J [C] 2.5 J [D] 2500 J [E] 2500 J/m [4] The length of a certain wire is doubled while its radius is reduced by a factor of 2. What is the change in the resistance of this wire? [A] It stays the same. [B] It is doubled. [C] It is quadrupled. [D] It increases by a factor of 6. /[Ejjlt increases by a factor of 8. ^-S [5] A number of resistors are connected across points A and B as shown in the figure. What is the equivalent resistance between points A and B? [A] 2 f t [B]4ft ^* 2O VWW- 2O 20 $ 6O % 4O B. " 20 20 20 § 8ft 10ft [6] An RC circuit is connected across a DC voltage source through an open switch. The switch is closed at t = 0 s. Which of the following is a correct statement regarding this circuit? [A] The capacitor charges to its maximum value in two time constants. [B] The resistor and the capacitor share the applied voltage equally as a function of time. [C The current flows through the circuit even after the capacitor is fully charged. nD / Once the capacitor is fully charged, there is no current in the circuit. [Ej The time constant does not depend on the resistance or the capacitance. Physics 102 [7] Positively charged particles, moving horizontally along the northward direction with a distribution of velocities, enter a region of space where both an electric and a magnetic field are present. These particles are to be selected according to their velocities. If the electric field points to the west, in what direction must the magnetic field point so that particles of the chosen velocity are undeflected? B should be vertical pointing up. [B] B should be vertical pointing down. B should be horizontal pointing east. [D] B should be horizontal pointing west. [E] B should be zero. t [8] The area of a rectangular loop of wire is 3.4 x 10~3 m2. The loop is placed in a magnetic field that changes from 0.20 T to 1.2 T in 1.6 s. The plane of the loop is perpendicular to the direction of the magnetic field. What is the magnitude of the induced emf in that loop? [A] 0 V [B] 1.1 x 10~3 V [C] 1.8 x 10-3 V @>2.1 x 10~3 V [E] 2.8 x 10~3 V [9] The primary coil of a t ransformer has 600 turns and its secondary coil has 150 turns. If the ac current in the primary coil is 2.0 A, what is the current in the secondary coil? [A] 0.50 A [B] 2.0 A ([C])8.0 A [D] 16 A [E] 20 A [10] According to the little metal plate on a hair dryer, it is rated at 120 Vrms and an average power of 1200 W. Assuming the load to be purely resistive (it really is not because of the motor), what is the maximum value of current in the dryer? [A] 10 A ([B])l4.1 A [C] 20 A [D] 28.2 A [E] none of these Physics 102 [11] Two point charges of magnitude q = 5.00 /xC, but of opposite signs, are placed at the vertices of the base of an equilateral triangle of side d = 2.00 m, as shown (the negative charge is placed to the right of the positive charge). Choose x and y coordinates, as shown, and find (a) the electric field at the third vertex, P, of the triangle, (b) the electric potential (relative to infinity) at the third vertex, P, of the triangle. (c) How much work has to be done to bring a test charge q0 = +2.00 /zC from very far away to the vertex P? (d) What is the net electric force acting on the test charge q0 (because of the other two charges) when it is at the vertex P? - o. Physics 102 [12] With the switch in position A, the Ci — 10.0 /izF capacitor in the figure is fully charged by the £ = 12.0 V b attery, and the C? = 14.0 /iF capacitor is uncharged. The switch is then moved to position B. As a result, charge flows between the capacitors until they have the same voltage across their plates. (a) Find the voltage across the plates of the capacitors when the switch is in position B. (b) What is the energy stored in each capacitor when the switch is in position A? (c) What is the energy stored in each capacitor when the switch is in position B? (d) Has the total energy stored in both capacitors increased or decreased by closing the switch? If it has increased, where do you think the additional energy came from? If it has decreased, what do you think happened to the missing energy? A: Q z (A)=o M-C, £ - lo,o- A S Physics 102 [13] The figure shows two parallel wires. Wire 1 carries a current /! = 5.0 A, flowing to the right. Wire 2 lies at distance 5 = 15 cm below wire 1, and point A lies at distance d = 10 cm below wire 2. The current I2 in wire 2 is adjusted so that the net magnetic field at point A is zero. (a) Does the current I2 flow to the right or to the left? (b) Express I2 in terms of the problem parameters, and calculate its numerical value. (c) An electron at point A has a velocity of v = 4.3 X 104 m/s parallel to wire 2 and to the right. What is the magnitude and direction of the force on this electron? Wirel Wire2 Aj (c) F - Physics 102 FORMULAE SHEET e = 1.60 x 10"19*?, me = 9.11 x lO"31*^, leV = 1.60 x 10"19 J, r* C/p -& ~ V' lkWh = 3.6 x 106J, g0 TT7 '' k = 8.99 x l09Nm2/C2 e0 = -r-r = 8.85 x 10~12(72/#m2 r" P/7 /7 A V rr = E 1 ' pf/" AA^-J-ATT" _ ~T " ~2~ • 2 C' AV /^Ac U " " ~ 2~' fco ^- V J r:= " A< T- = f - p-S.iv.i...^ *.*«+..., i-i+i+... ont, (7p = C 'i+C r 2 + . . . , 2^ ^ = 2_/ -^-Rj ^"=Cr + ^~ + " ^1 /T)], - = \q\vB, J=-expH/r), F = ItBsi^6, /i ng) ' (l° \ $6=5,400561, AJ „ VB — ~^~? L-\L B2 U B £ = vBl, A/ At I 2 LI 5 = -- -~, ~ — ^~~5 Ns Vs _ Ip -i*Ti 'n "JTT" — TT — T~5 -J-s g = Q exp ( -t/r), T = NIABsinO, oj 2?ra ' J=| /z0 = 4?r x 1 0~ 7 —— /• -n (coil) £ = NABusinut, ti - j\ (solenoid) ' u> = 2?r _L PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #6 Prof. J. Ashkenazi Chapter 25 Suggested Problems: 3, 5, 8, 9, 11, 15, 17, 19, 25, 29, 33, 35, 37, 41, 43, 47, 49, 51, 53, 59, 65, 66, 67, 69 Problems to be submitted on June 5, 2007: 4, 16, 20, 36, 40, 58, 60, 70, 72 File translated from TEX by TTH, version 3.40. On 30 May 2007, 10:29. http://www.physics.miami.edu/ashkenazi/102_sum/hw6.htm [7/31/2007 8:51:39 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #7 Prof. J. Ashkenazi Chapter 26 Suggested Problems: 1, 7, 9, 10, 13, 17, 19, 23, 24, 25, 30, 31, 34, 37, 41, 43, 47, 49, 63, 67, 69, 77 Problems to be submitted on June 7, 2007: 2, 12, 28, 32, 46, 50, 54, 68, 72 Chapter 27 Suggested Problems: 16, 17, 19, 20, 21, 27, 28, 29, 31, 37, 41 Problems to be submitted on June 7, 2007: 24, 42 File translated from TEX by TTH, version 3.40. On 1 Jun 2007, 11:34. http://www.physics.miami.edu/ashkenazi/102_sum/hw7.htm [7/31/2007 8:51:40 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #8 Prof. J. Ashkenazi Chapter 28 Suggested Problems: 1, 3, 9, 13, 17, 23, 25, 33, 36, 37, 39, 43, 47, 53, 57, 61, 63 Problems to be submitted on June 11, 2007: 4, 20, 30, 32, 44, 52, 60, 64 File translated from TEX by TTH, version 3.40. On 6 Jun 2007, 11:10. http://www.physics.miami.edu/ashkenazi/102_sum/hw8.htm [7/31/2007 8:51:41 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #9 Prof. J. Ashkenazi Chapter 29 Suggested Problems: 1, 3, 9, 15, 19, 25, 27, 31, 32, 35, 41, 43, 49, 51, 53, 55, 57, 62, 63, 64, 84 Problems to be submitted on June 13, 2007: 8, 10, 26, 28, 36, 38, 46, 56, 58 File translated from TEX by TTH, version 3.40. On 7 Jun 2007, 11:06. http://www.physics.miami.edu/ashkenazi/102_sum/hw9.htm [7/31/2007 8:51:42 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #10 Prof. J. Ashkenazi Chapter 30 Suggested Problems: 1, 3, 7, 11, 15, 17, 19, 23, 25, 31, 33, 35, 41, 43, 47, 51, 53, 55, 57, 61, 63, 65, 67 Problems to be submitted on June 14, 2007: 8, 20, 28, 36, 46, 54, 66, 68 File translated from TEX by TTH, version 3.40. On 11 Jun 2007, 10:29. http://www.physics.miami.edu/ashkenazi/102_sum/hw10.htm [7/31/2007 8:51:43 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt21.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt21.jpg (1 of 2) [7/31/2007 8:51:45 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt21.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt21.jpg (2 of 2) [7/31/2007 8:51:45 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt22.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt22.jpg (1 of 2) [7/31/2007 8:51:47 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt22.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt22.jpg (2 of 2) [7/31/2007 8:51:47 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt23.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt23.jpg (1 of 2) [7/31/2007 8:51:49 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt23.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt23.jpg (2 of 2) [7/31/2007 8:51:49 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt24.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt24.jpg (1 of 2) [7/31/2007 8:51:50 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt24.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt24.jpg (2 of 2) [7/31/2007 8:51:50 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt25.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt25.jpg (1 of 2) [7/31/2007 8:51:52 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt25.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt25.jpg (2 of 2) [7/31/2007 8:51:52 AM] Physics 102 [l] The wavelength of an electromagnetic wave is 600 nm. What is its frequency? [A] 100 x 1012 Hz ([EP500 x 1012 Hz [B] 200 x 1012 Hz [C] 300 x 1012 Hz [D] 400 x 1012 Hz [2] A 60.0 W (average power) light bulb radiates light uniformly in all directions. What is the rrns value of the magnetic field of the radiation at a distance of 0.400 m from the bulb? [A] 9.87 x 10~8 T [B] 1.76 x 10~7 T [C] 2.22 x 10~7 T (^3.53 x 10~7 T T [E] 5.72 x 10~ T ^^ [3] A vertically polarized beam of light of intensity 100 W /m 2 passes through two ideal polarizers. The transmission axis of the first polarizer makes an angle of 20° to the vertical, while for the second one this angle is 4 0°, in the same sense . What is the t ransmitted intensity of the beam of light (after the second polarizer)? [A] 11.7 W /m 2 [B] 37.2 W /m 2 [C] 44.4 W /m 2 [D] 66.6 W /m 2 (M78.0 W /m 2 [4] An object 4.0 cm in height is placed 8.0 cm in front of a concave mirror of focal length 10.0 cm. What is the position of its image in relation to the mirror, and what are its characteristics? [A] 10.0 cm on the other side of the mirror, virtual, 10.0 times bigger [B] 10.0 cm on the same side of the mirror, real, 6.0 times bigger ^Cj)40.0 cm on the other side of the mirror, virtual, 5.0 times bigger [D] 40.0 cm on the other side of the mirror, real, 6.0 times bigger [E] none of the above [5] Light is propagating from diamond (n — 2.42) into crown glass (n = 1.52). Find the critical angle for total internal reflection. (Q)39° [B] 45° [C] 51° [D] 79° [E] 90° [6] White light is passed through a diffraction grating t hat has 250 l ines/mm. On each side of the white central maximum, a spectrum of colors is observed. What is the wavelength of the light observed at an angle of 7.00° in the first order bright fringes? [A] 417 nm ($$481 nm [C] 589 nm [D] 632 nm [E] 668 nm [7] A stronaut Rachel leaves Earth in a spaceship at a speed of 0.960c relative to an observer on Earth. Rachel's destination is a star system 14.4 light-years away, as it is viewed f rom Earth. According to Rachel, how long does the trip take? (One light-year is the distance Ught travels in one year.) JJAJ)4.20 years [B] 14.4 years [C] 15.0 years [D] 22.7 years [E] 53.6 years [8] What is the surface t emperature of a s tar, given that its radiation peak occurs at a frequency of 1.06 X 1015 Hz? [A] 14,500 K [B] 17,000 K (fC| 18,000 K [D] 20,400 K [E] 24,600 K Physics 102 [9] A beam of light with a frequency range of 3.01 X 1014 Hz - 6.10 X 1014 Hz is incident on a metal surface. If the work function of the metal surface is 2.20 eV, what is the maximum kinetic energy of photoelectrons ejected from the surface? [A] 0.11 eV [ B]0.16eV [C] 0.21 eV ([9)0.32 eV [E] 0.42 eV [10] A certain photon, after being scattered from a free electron at rest, moves at an angle of 120° with respect to the incident direction. If the wavelength of the incident photon is 0.571 nm, what is the energy of the scattered photon? [A] 1.05 x 1Q-16 J ([Bj)3.46 x 10~16 J [C] 5.71 x 10~16 J [D] 7.25 x 10~16 J [E] 9.10 x 10~16 J [13] (a) (b) (c) Consider a particle of rest mass m0 = 1.00 kg, moving at speed v = 0.866c. Calculate the rest energy, total energy, and kinetic energy of the particle in units of kg • <?. Calculate the momentum of the particle in units of kg • c. What is the work (in units of kg • c2) necessary to accelerate the particle from rest to its speed of 0.866c? E = t}+ f ^ ? ^> p-^J^^^,/I^^u^ - A E = 6- ^ - ft.oo- Physics 102 [11] Two lenses that are 50.0 cm apart are used to form an image, as shown. The lenses are converging and each has a focal length of 20.0 cm. The object is placed 30.0 cm to the left of lens 1. The two lenses have the same optical axis. Find (a) the location of the first image (due to lens 1), (b) the location of the final image (due to lens 2), (c) the magnification of the final image relative to the (initial) object. (d) Is the final image real or v irtual? Is it upright or inverted with respect to the (initial) object? Object £ - — do \ L - i / ' £0. X: — dii ' ~ - - - — > 01 Physics 102 [12] Monochromatic light of wavelength A = 600 nm shines down on a planoconvex lens of radius of c urvature R = 10.0 m lying on a piece of plate glass, as shown. The result of the interference between light reflected from the b ottom surface of the lens, and light reflected from the top surface of the plate is a set of concentric dark rings, when viewed from above. (a) Express in terms of m and A the value of the separation t between the surfaces of the lens and of the plate, for which the m1*1 dark ring is viewed. (b) Express in terms of R and t the radius r of the dark ring, for which the separation between those surfaces is t. (c) Calculate the numerical values of t and r for the 20th dark ring. /!\ ^-=0 t (t) r = ? Planoconvex lens rs (C) ^ = •=_£.ooH w . Physics 102 FORMULAE SHEET e = 1.60 x 10~~19a, me = 9.11 x 10~31%, leV = 1.60 x 10~19 J, V = —, qo = 8.85 x lQ-l2C2/Nm IkWh = 3.6 x 106J, WE = q0Ed = -g0AF, mv F = qvBsin6, k = 8.99 x Wnc = &K + AC/, qvB, F = I£Bsm0, , 27T „ AF = -£As, .,„ T = NIABsin0, 1 c= /i m = ^ PFsinfl = m A, 7 7 i = l , 2 . . . , (single slit, d ark) in f ilm "i<"<"2 o r n i > n > n \i in. illlll, rai<n>n2 or m >7i<n 22 J / bright-, Uark ) 1 771 _ moc 7 j2/ c 2 111 /"/i V\ -\- V2 ,, : n -D-I / A' -, . T> = TTlQV : = TTlt) 2GM = E-E, o, eF n m c ft = _ = 1.054 x 10~34 J 2?r = 5.88 x 7 7^1 p = — = -, c A MB ,_ A— fdark ^ Vbright 1 h = 6.626 x 10~34J s = 4.135 x 10~15eF s = 1240 A P T = 2.898 x 1 0- 3 m-# — J i COS T' dsin6l = (m + l /2)A, m = 0 ,1,2 . . . , (double slit, dark) a . r^ l o oA 7/ "nun '^ *•«* n > y •n n — ~ sin u KI " (resolution) L , m = 0 ,1,2 . . . , (double slit, grating, bright) 2 /o n •"m' A<o : c v = -, " =- TL2 2, A/ = c = 3.00 x AC/ sn I = n2 s n F =— r _ 7 Tm //„ = 4ir X 10 T A'-A = A c = - = 2.426 mec AEAi > - P ** PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #11 Prof. J. Ashkenazi Chapter 31 Suggested Problems: 1, 2, 3, 9, 13, 17, 21, 23, 29, 31, 33, 35, 40, 41, 45, 47, 49, 50, 51, 53, 55 Problems to be submitted on June 19, 2007: 4, 10, 20, 22, 30, 36, 44, 46, 54, 56 File translated from TEX by TTH, version 3.40. On 13 Jun 2007, 10:47. http://www.physics.miami.edu/ashkenazi/102_sum/hw11.htm [7/31/2007 8:52:01 AM] PHYSICS 102 A --- Summer 1 2007 PHYSICS 102 A - Summer 1 2007 Suggested Problems and Homework #12 Prof. J. Ashkenazi Chapter 32 Suggested Problems: 1, 3, 7, 9, 13, 17, 19, 23, 27, 29, 35, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 Problems to be submitted on June 20, 2007: 2, 10, 18, 30, 32 File translated from TEX by TTH, version 3.40. On 18 Jun 2007, 10:33. http://www.physics.miami.edu/ashkenazi/102_sum/hw12.htm [7/31/2007 8:52:02 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt31.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt31.jpg (1 of 2) [7/31/2007 8:52:04 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt31.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt31.jpg (2 of 2) [7/31/2007 8:52:04 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt32.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt32.jpg (1 of 2) [7/31/2007 8:52:06 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt32.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt32.jpg (2 of 2) [7/31/2007 8:52:06 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt33.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt33.jpg (1 of 2) [7/31/2007 8:52:08 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt33.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt33.jpg (2 of 2) [7/31/2007 8:52:08 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt34.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt34.jpg (1 of 2) [7/31/2007 8:52:09 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt34.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt34.jpg (2 of 2) [7/31/2007 8:52:09 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt35.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt35.jpg (1 of 2) [7/31/2007 8:52:11 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt35.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt35.jpg (2 of 2) [7/31/2007 8:52:11 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt36.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt36.jpg (1 of 2) [7/31/2007 8:52:12 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt36.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt36.jpg (2 of 2) [7/31/2007 8:52:12 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt37.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt37.jpg (1 of 2) [7/31/2007 8:52:14 AM] http://www.physics.miami.edu/ashkenazi/102_sum/pt37.jpg http://www.physics.miami.edu/ashkenazi/102_sum/pt37.jpg (2 of 2) [7/31/2007 8:52:14 AM] Physics 102 [l] Two point charges of —10.0 fj-C and +3.00 fiC are separated by a distance of 20.0 cm. What are the magnitude and direction of the electric field midway between these two charges? [A] 0.63 X 107 N/C directed towards the negative charge J210.63 X 10T N/C directed towards the positive charge ([Cj}l.l7 X 107 N/C directed towards the negative charge [D] 1.17 x 107 N/C directed towards the positive charge [E] 3.51 X 107 N/C directed towards the negative charge [2] The electric potential at x - 2.00 m is +200 V, and at x = 8.00 m is -1000 V. What is the magnitude and direction of the electric field? [A] 100 V /m in the -x direction (J5})200 V /m in the +x direction [C] 300 V/m in the -x direction [D] 400 V/m in the +x direction [E] 500 V/m in the -x direction [3] The resistivity of a 1.0 m long wire is 1.72 X 10~8 fi-m, and its cross sectional area is 1.0 X 10~6 m 2 . If the wire carries a current of 0.10 A, what is the voltage across the wire? 7 mV [B] 3.4 mV [C] 16 mV [D] 20 mV [E] 34 mV [4] An electron moving perpendicular to a magnetic field of 4.2 X 10~2 T moves in a circle of radius 0.20 cm. How fast is this electron r npving? [A] 2.5 x 10-53 m /s [B] 2500 m/s (lCJ)l.5 x 107 m/s [D] 1.5 x 109 m/s 9 [E] 8.0 x 10 m/s [5] A solenoid with a certain number of t urns N, and carrying a current of 2.000 A, has a length of 34.00 cm. If the magnitude of the magnetic field generated at the center of the solenoid is 20.00 mT, what is the value of TV? [A] 1055 [B] 1353 [C] 1591 (JDj)2706 [E] 4601 [6] A conducting rod w ith a length of 25 cm is placed in a U-shaped metal wire that has a resistance R of 4.0 f i, as shown in the figure. The wire and the rod are placed in the plane of the paper. A constant magnetic field of strength 0.40 T is applied perpendicular into the paper. An applied force moves the rod to the right with a constant speed of 6.0 m /s. What is the magnitude and direction of the induced current in the wire? [A] 17 mA counterclockwise [B] 75 mA clockwise [D] 0.15 A clockwise ([El/ 0.15 A counterclockwise F applied [C] 75 mA counterclockwise Physics 102 [7] The average intensity of the sunlight in Miami, Florida, is 1060 W /m 2 . What is the average value of the radiation pressure due to this sunlight in Miami? [A] 2.28 x !0~ 6 N /m 2 @3.53 x !0~ 6 N /m 2 [C] 9.78 x lO~ 6 N /m 2 5 2 5 2 [D] 1.05 x lO~ N /m [E] 1.63 x lO~ N /m [8] A nearsighted person has a far point that is 2.6 m from his eyes. What focal length lenses must he use in his contact lenses to allow him to focus on distant objects? [A] -2.1 m [B] 2.1 m (fc)-2.6 m [D] 2.6 m [E] none of the above [9] What is the minimal non-zero thickness of a soap bubble (n = 1.42) that results in a constructive interference in the reflected light if this film is illuminated (at normal incidence) by a beam of light of wavelength 451 nm? ([AJ579 nm [B] 106 nm [C] 159 nm [D] 212 nm [E] 318 nm [10] Two spaceships approach Earth from opposite directions; one at a speed of 0.81c, and the other at a speed of 0.94c, both relative to E arth. What is the speed of one spaceship relative to the other? [A] 0.41 c [B] 0.45c [C] 0.54c (15) 0.9935c [E] 1.75c [ll] An electron is moving with a speed of 445 m/s. What is its de Brqglie wavelength? [A] 410 nm [B] 817 nm [C] 1000 nm [D] 1290 nm (JEJ)1630 nm [12] In a hydrogen atom, the electron makes a transition from the n = 8 to the n — 4 state. What is the wavelength of the emitted photon? [A] 3.12 x 10~7 m [B] 9.54 x 10~7 m [C] 1.13 x 10~6 m (JDJ)l.94 x 10~6 m 6 [E] 3.25 x ID" m [13] Which one of the following is the correct ground state electronic configuration of the carbon atom (Z = 6)? [B] I s 2 2s 2 2p 6 [C] I s 2 2s 2 2p 6 3s 2 [D] I s 2 2s 2 2p 6 3s 2 3p 2 [14] Estimate the Ka (i.e. due to a transition from the L shell to the K shell) X-ray wavelength for a gold atom (Z = 79 ). [A] 2.47 x 10~13 m @)2.00 x lO"11 m [C] 3.60 x lO"11 m 10 10 [D] 5.13 x lO" m [E] 8.54 x 10~ m [15] Carbon-14 has a half-life of 5730 years. A sample of wood has been recovered by an archaeologist. The sample is sent to a laboratory, where it is determined that the activity of the sample is 0.104 Bq/g. By comparing this activity with the activity of living organic matter, 0.230 Bq/g, the scientist determines how old the wood sample is, or more precisely, when the tree that the sample came from died. How old is the sample of wood? [A] 2630 years [B] 3870 years [C] 4590 years [D] 5730 years ([E]) 6560 years Physics 102 [16] The circuit shown in the figure consists of a 10.0-V battery, a 30.0-mH inductor, four 30.0-ft resistors, and a switch. (a) Find the time constant r for this circuit. (b) What is the current supplied by this battery three time constants after closing the switch? (c) How much energy is then stored in the inductor? (d) Assuming that the inductor is an air-filled solenoid of cross-sectional area 0.0300 m2 and 450 t urns, find its length. d-' u LI 2 " ., JM) So-o A d- o .o D A=o, 3 ^ =5) { -^ L a ~IT Physics 102 [17] The observer in the figure is positioned so that the far edge of the b ottom of the empty glass is just visible. When the glass is filled to the top with water (n = 1.33), the center of the bottom of the glass is just visible to the observer. Find the height, H, of the glass, given that its w idth is W — 6.0 cm. H*l s^<u \A/ JV^HH 1 Svh^ W/i ^^ T fH I ^ (Wf+Hl -w- H') - ^ I /+ l*iL X = \ i; = 3. , /i — , — , =t ? ,.l Physics 102 [18] Consider the fusion reaction ^ H +\ H —>| He + 7, where the (neutral) atomic masses are: m(lE) = 2.014102 u, m(|He) = 4.002603 u. (a) Write down an algebraic expression for the energy produced in this reaction in terms of m(iH) a nd m(|He). (b) Calculate the energy produced in this reaction in MeV units. (c) How many kilowatt-hours (kWh) are released when 1.00 kg of deuterium ( jH) undergo this reaction? / -D.D2S-CO/ H - NU - - in fs w ^ ~ - °° Physics 102 FORMULAE SHEET I e = 1.60 x 10~19(7, 2 9 = 8.99 x W9 Nm2/C2 me = 9.11 x leV = 1.60 x 10-19J, 106J, — = 8.85 x W~i2C2 /Nm2 e0 = - 4 Ae0 V=—, qo . V' , WE = -^L «' r - K€°A Wnc = nE (2 ' (7£[l-erp(-i/T)], "" 2 - 2 - " "2C7' / = - exp ( -i/r), *" = ?r x , ' (coil) ' £ = NABusinwt, —-, E = cB, (solenoid) 2?r — X =- AJ JS = E 0 sin(A;x - w<), fc = -^, A< g = Q exp = \q\vB, (bng) T- 2' c= _ = 3.00 x 108m/.s, \f = c Physics 102 FORMULAE SHEET II c = ~> n sin #1 = n2 sin # 2, sin$c = — , T> = — f infl = ( m (double slit, dark) (double slit, grating, bright) (single slit, d ark) (thin film, — = — -f — , J h h t an0 B = — , Avac n (resolution) %$££) r L= = mv v— R= = 6.626 x 10~34J 5 = 4.135 x 10~15eF 5 = 1240 6 nm , a = — = 1.054 x 10~34 J C pr , = 2.898 x 27T E = hf = 5.88 x =- = ^, c A A c = — = 2 .426pm mec \'-\ = > -, 2 A dB = -, = 0.0529 nm, En - --B0^-, -' n = l,2,3,...; ^= o nQ7v1fl7 2 ~ = 13.6 2a0 -1 = 1-097x10 m , t = 0 ,1, . . . , n - 1; mt = 0, ± 1, . . . , ±1; ms = ± A T^, = A mc 2 , A = Z + 7V, r = r 0 A 1/3 , 1 u = 1.6605 x 10~27A;5 = 931.5 M eF/c 2 , ~ = \N, N = N0exp(-Xt), Ac r 0 = 1.2 /m 7VA = 6.022 x l O^ X = ~, f = i ln^, 1 Ci = 3.70 x Ji A xt 1. It is strictly forbidden to 1. It is strictly forbidden to use a cellular phone during an exam. Students caught with their cellular phones on, during an exam, WILL BE FAILED. 2. It is strictly forbidden to use a calculator with graphic, programming, and communication capabilities during an exam. Students caught using such a calculator, during an exam, WILL BE FAILED. 3. It is allowed to use only a "one-line" calculator, and students who do not have one are urged to get it before the next exam (they are cheap). File translated from TEX by TTH, version 3.40. On 9 Mar 2004, 14:12. http://www.physics.miami.edu/ashkenazi/102_sum/exams.htm [7/31/2007 8:52:25 AM] ...
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This note was uploaded on 10/19/2011 for the course PHY 102 taught by Professor Korotkova during the Spring '09 term at University of Miami.

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