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Unformatted text preview: Exam 3- Practice Exam Phys 2426 Fall 2008 Name___________________________________ You may use a pencil, eraser, calculator and three 4 x 6 inch hand written index cards. You may obtain extra paper from the instructor if needed. Staple any extra sheets to the back of the exam. k e =(1/4 ΔΉ o ) = 8.99 x 10 9 Nm 2 /C 2 m e = 9.11 x 10-31 kg Ή o = 8.85 x 10-12 C 2 /Nm 2 m p = 1.67 x 10-27 kg e = 1.602 x 10-19 C MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Alpha particles (charge = + 2 e , mass = 6.68 × 10- 27 kg) are accelerated in a cyclotron to a final orbit radius of 0.60 m. The magnetic field in the cyclotron is 0.10 T. The period of circular motion of the alpha particles is closest to: A) 2.6 μs B) 2.0 μs C) 1.3 μs D) 3.9 μs E) 3.2 μs Figure 27.1 2) In Fig. 27.1 is a velocity selector that can be used to measure the speed of a charged particle. A beam of particles is directed along the axis of the instrument. A parallel plate capacitor sets up an electric field E , which is oriented perpendicular to a uniform magnetic field B . If the plates are separated by 8 mm and the value of the magnetic field is 0.3 T, what voltage between the plates will allow particles of speed 5 × 10 5 m/s to pass straight through without deflection? A) 1200 V B) 3800 V C) 7500 V D) 190 V E) 380 V 1 Figure 27.6 3) In Fig. 27.6, a wire segment 1.2 m long carries a current I = 3.5 A, and is oriented as shown. A uniform magnetic field of magnitude 0.50 T is present as shown. Right- handed coordinates are used. The magnetic force on the wire segment, in SI units, is closest to: A)- 1.1 j- 1.8 k B)- 1.8 j + 1.1 k C) + 1.1 j- 1.8 k D) + 1.8 j- 1.1 k E)- 1.1 j + 1.8 k Figure 27.7a 4) A rigid rectangular loop, which measures 0.30 m by 0.40 m, carries a current of 9.9 A, as shown. A uniform external magnetic field of magnitude 1.8 T in the negative x- direction is present. Segment CD is in the x- z plane and forms a 19° angle with the z- axis, as shown. In Fig. 27.7a, the y- component of the magnetic force on segment AB is closest to: A) + 1.7 N B) + 5.1 N C)- 5.1 N D)- 1.7 N E) zero 5) Ions having equal charges but masses of...
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