Physics 30 Dec 2000 Diploma Exam

Use appropriate formulas to support your answer note

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Unformatted text preview: ins on the next page. 25 Use the following information to answer the next question. Cyclotron A cyclotron is a particle accelerator that is constructed of two hollow metal shells shaped like Ds in a perpendicular magnetic field created by magnets, as shown below. The entire apparatus is placed in a vacuum. An alternating voltage is maintained across the D separation. Positively charged particles such as protons are injected near the centre of the Ds and travel in circular paths caused by the external perpendicular magnetic field. The frequency of the alternating voltage is adjusted to increase the speed of the particles each time they move across the Ds’ separation. Upper magnet Injection point Ds Path of protons D separation Lower magnet Cyclotron Specifications Magnetic field intensity Maximum voltage across D separation D separation 0.863 T 20 000 V 5.00 cm Written Response — 15% 2. • Determine the direction of the magnetic field needed to cause protons to circle in the direction shown. Justify your answer. • Calculate the radius of the path of a proton travelling at 2.50 × 106 m/s. • Calculate the speed of a proton after it passes once between the Ds, if it enters the space between the Ds at 2.50 × 106 m/s. 26 Use the following information to answer the remainder of this question. The speed of a particle moving with circular motion and the time it takes the particle to complete one circular orbit are given by the formulas v= 2π R 2π m and T = T qB⊥ • Beginning with force equations from the tear-out sheets, derive the formula for the period 2π m T= qB⊥ • Show that the units of 2π m are equivalent to seconds. qB⊥ Clearly communicate your understanding of the physics principles that you are using to solve this question. You may communicate this understanding mathematically, graphically, and/or with written statements. 27 You have now completed the examination. If you have time, you may wish to check your answers. 28 n = 1.00 c = 3.00 × 10 m/s Index of Refraction of Air................... Speed of Light in Vacuum .................. eV.s e = 1.60 × 10 Elementary Charge.............................. C –27 –31 –27 –27 mα = 6.65 × 10 m e = 9.11 × 10 m n = 1.67 × 10 m p = 1. 67 × 10 Alpha Particle ............... Electron ........................ Neutron ......................... Proton ........................... Rest Mass kg kg kg kg –11 m 2+ + 0 – p n e α Charge 7 RH = 1.10 × 10 1 Rydberg’s Constant for Hydrogen ...... Particles r1 = 5.29 × 10 Radius of 1st Bohr Orbit of Hydrogen m J.s or 4.14 × 10 –34 h = 6.63 × 10 Planck’s Constant ............................... –15 J or –13.6 eV J E1 = – 2 .18 × 10 8 –19 –19 –18 Energy of an Electron in the 1st Bohr Orbit of Hydrogen ..................... Atomic Physics 1 eV = 1.60 × 10 Electron Volt....................................... 2 2 Symbol –3 –6 –9 –12 deci .............. d ..................10 centi ............. c ................
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This note was uploaded on 01/14/2014 for the course PHYSICS Physics 30 taught by Professor Quinlan during the Fall '09 term at Centennial High School.

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