General Physics Laboratory - Practice Final Questions | PHYS 202, Exams of Physics

Download General Physics Laboratory - Practice Final Questions | PHYS 202 and more Exams Physics in PDF only on Docsity! ALEXANDER CARMOEGA - Physics 202 / Winter 2011 1 Practice Exams March 17, 2010 PHYSICS 202 Practice Final, Winter 2009-10 YOUR NAME: OAK Login ID: @ohio.edu Section (circle one) (8-9: Piccard) (11-12: Lucas) (2-3: Tees) NOTE: For credit in Part B you MUST show all your work. NO credit will be given in the long problems for just a numerical solution. Unless noted, a correct solution MUST include the correct numerical value with 3 significant figures and correct UNITS. If you need more space for your work, please use back of sheets. Numerical Constants and Conversions: femto 10−15; pico 10−12; nano 10−9; micro(µ) 10−6; milli 10−3; centi 10−2; kilo 103; Mega 106; Giga 109; g = 9.80 m/s2; ke=8.99×10 9 N·m2/C2 T(K) = T(◦ C) + 273 ǫ0 = 8.85 × 10 −12C2/N · m2 1kW-hr = 3.6×106J µ0 = 4π × 10 −7 T·m/A kB = 1.381×10 −23J/K κvacuum = 1.0 R = 8.314 J/(mol·K) |e| = 1.60×10−19C 1-eV = 1.60×10−19J Water: Specific Heat = 4186 J/kg·◦C Lvaporization = 2.26×10 6J/kg Specific Heat(Ice) = 2090 J/kg·◦C Lfusion = 3.33 ×10 5J/kg Specific Heat(Steam) = 2010 J/kg·◦C Unless otherwise specified use 343m/s for the speed of sound in air. ASQUARE = l 2 ACIRCLE = πr 2 VCYL = πr 2h The following questions are a collection of questions that have been used on previous exams or are very similar to previous exam questions. The difficulty obviously varies. Please understand that no single exam will cover all of the material covered in Physics 202. Just because certain material did not show up on this practice exam, that does not mean that the material will not show up on the final. If the number of points on this exam add up to 100, it is purely by accident. 1 Part A - Multiple Choice/True-False (Points as labelled) 1. A rope fixed at both ends has a length of 1.2m and total mass of 110g. The fundamental frequency of this rope is 40 Hz. (a) (2 pts) What is the frequency of the 5th harmonic? (a) 1.2 Hz (b) 40 Hz (c) 50 Hz (d) 200 Hz (e) 550 Hz (b) (3 pts) Draw the fifth harmonic on the string below. String 2. (3 pts) The drawing shows two thin rods, one made from aluminum ( α = 23 × 10−6(◦ C)−1) and the other from steel (α = 12 × 10−6(◦ C)−1). Each rod has the same length, the same initial temperature, and is attached at one end to an immovable wall, as shown. The cross-sectional area of the rods is 3.4×10−4m2. The temperatures of the rods are increased, both by the same amount, until the gap between the rods is closed. Where do the rods meet when the gap is closed? Aluminum Steel midpoint (a) The rods meet exactly at the midpoint. (b) The rods meet to the right of the midpoint. (c) The rods meet to the left of the midpoint. 3. (3 pts) A parallel plate capacitor is constructed from two plates placed 3 mm apart. If the two plates are moved to a distance of 6 mm apart, the new capacitance is times the original capacitance. (a) 1/8 (b) 1/4 (c) 1/2 (d) 1 (e) 2 (f) 4 (g) 8 2 10. A charged particle is sent into a mass spectrometer with a uniform magnetic field pointing out of the paper. It follows the path shown and passes through the slit where it hits a detector. You now send particles into the spectrometer with double the mass and half the charge. You want these particles to pass through the same slit as before, so you adjust the magnetic field. B Detector v (a) (2 pts) The new magnetic field is times the original field. (a) 1/8 (b) 1/4 (c) 1/2 (d) 1 (e) 2 (f) 4 (g) 8 (b) (1 pt) What is the charge of the particle? (circle one) positive negative 11. 4 resistors are arranged as shown. The voltage across the combination is 120V and the current through R1 is 0.4A. (a) (3 pts) The current through R2 is the current through R3. (a) greater than (b) equal to (c) less than (b) (3 pts) What is the potential at point A? (a) 30V (b) 40V (c) 80V (d) 90V (e) 120V (f) 160V 0V +120V R1=100 Ω Ω A R4=300Ω R3=300Ω R2= 300 12. (3 pts) Two wires are shown below. A current of 5A flows upward in wire 1. A current of 10A flows upward in wire 2. Consider the magnetic field at a point midway between the wires. What is the direction of the net field at this point? (circle one) Wire 1 Wire 2 Midpoint Field is zero 5 13. There are 4 particles moving in a uniform magnetic field as shown in the figure. What is the sign of the charge on each of the particles? (a) (1 pt) Particle A - 0 + (b) (1 pt) Particle B - 0 + (c) (1 pt) Particle C - 0 + (d) (1 pt) Particle D - 0 + C A B D 14. Three identical light bulbs (A, B and C) are connected to a battery as shown. B CA (a) (2 pts) Bulb C is removed from its socket. Bulb B glows (a) Brighter (b) The same as before (c) Dimmer (d) Not at all (b) (2 pts) Bulb C is placed back in its socket and Bulb A is removed. Compared to its original brightness (with all three bulbs in place), Bulb B now glows (a) Brighter (b) The same as before (c) Dimmer (d) Not at all (c) (2 pts) With all three bulbs in place, the current through bulb A is the current through bulb C. (a) greater than (b) equal to (c) less than 15. (3 pts) The following plot represents the displacement from equilibrium of an object attached to a horizontal spring. The object is sliding back and forth on a frictionless tabletop. At which point or points is the kinetic energy of the object the greatest? 0 t(s) X(m) A B C D E F G (a) A (b) B (c) C (d) D (e) E (f) F (g) G (h) A and D (i) C and E 6 Part B For full credit, you MUST show the work done to get the answers. Your work MUST be written clearly enough to be understood. Make sure that units are included with answers when appropriate. NO partial credit will be given for just answering correct units. 1. (11 pts) A copper rod of length 0.45m is lying on a frictionless table (see the figure). Each end of the rod is attached to a fixed wire by an unstretched spring whose spring constant is 75N/m. A magnetic field with a strength of 0.32T is oriented perpendicular to the surface of the table. (In the following ignore any effects due to fact that the current also flows through the springs.) (a) (2 pts) What is the direction of the current in the copper rod that causes the springs to stretch? (a) to the right (b) to the left (b) (3 pts) If the current through the rod is 11 A, what is the force on the rod due to the magnetic field? Answer: Units: (c) (3 pts) By how much does each spring stretch? Answer: Units: (d) The current of 11A is achieved by attaching the wires to a voltage of 35V. The radius of the copper rod is now doubled while the voltage is held constant. The experiment is repeated. (i) (1 pt) Will the springs stretch more or less than before? (circle one) (ii) (2 pts) If the resistance of the springs and external wire are considered to be 0, the new displacement is times the old displacement. (a) 1/8 (b) 1/4 (c) 1/2 (d) 1 (e) 2 (f) 4 (g) 8 7 (c) (4 pts) The specific heat of Ar is 520 J/kg-K and that of Ne is 1030 J/kg-K. Equal amount of heat, 150 J, is injected into each container. The total mass of the argon in container A is 0.040 kg. The total of the Neon in container B is 0.010 kg. Find the final temperature of Ar and Ne in their respective compartments. Argon: Neon: (d) (3 pts) Now the thermally insulating barrier C is removed and the contents of the two com- partments are free to mix. Find the final temperature of the mixture after thermal equilibrium is attained. Answer: (e) (2 pts) After thermal equilibrium is attained, what is the relationship between the kinetic energy of the Ar atoms to that of the Ne atoms? i. KE Ar > KE Ne ii. KE Ar < KE Ne iii. KE Ar = KE Ne iv. not enough information is available to answer this question 10 4. (13 pts) A velocity filter is used to select particles of a given velocity before they enter a mass spectrometer. This filter uses a pair of parallel plates to set up an electric field of 1800 V/m. The plates are separated by a distance of 0.035m. A uniform magnetic field is set up in the same region with the field pointing into the paper. Ions with a net charge of +1.60×10−19C are sent into the velocity filter. You would like to select particles with a speed of 3.0×105m/s. + v B Top Plate Charged Parallel Plates Bottom Plate (a) (3 pts) What is the strength of the electric force on a single ion? Answer: Units: (b) (1 pt) What is the direction of the magnetic force? (circle one) (c) (3 pt) What is the strength of the magnetic field required to select the particles with speeds of 3.0×105m/s. Answer: Units: (d) (1 pt) What is the direction of the electric field? (circle one) (e) (1 pt) Which plate has a net negative charge? Top Bottom (Circle one) (f) (3 pt) What is the potential difference required between the two plates in order to obtain this field? Answer: Units: (g) (1 pt) If a particle that was faster than the previous particle were injected, which of the following trajectories would it follow? (circle the number) B 3 2 1 11 Printed from LON-CAPA©MSU Licensed under GNU General Public License