FinalExam_Phys9HD_2009

FinalExam_Phys9HD_2009 - FINAL EXAMINATION Physics 9HD Fall...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 FINAL EXAMINATION Physics 9HD Fall 2009 December 10, 2009 NAME_______________________________________________________________________ You are permitted to bring and use three 8 /1/2” x 11” sheets of paper with formulas, and your calculator. 8 QUESTIONS . MAXIMUM SCORE IS 150 POINTS. SHOW ALL OF YOUR WORK. ______________________________________________________________________________ 1. (30 points) You are going to calculate the properties of an ultrarelativistic proton, with mass m, as it passes first through an accelerating voltage, followed by a velocity selector. Assume that the initial velocity of the proton is zero. See the diagram of the arrangement in the lab frame below. (a) (5 points) The proton will gain energy from the accelerating voltage V along x ) . Find its velocity after it passes through the electric field caused by the accelerating voltage. (b) (5 points) Next, the proton passes through velocity selector, which is a region of crossed uniform electric and magnetic fields. The fields are both perpendicular to the particle’s velocity and to each other, i.e., z B B y E E x v v ) r ) r ) r = = = , , (see diagram). Derive an expression for the magnitude of the velocity v, in terms of the magnitudes of the electric and magnetic fields, E and B, if the proton’s velocity v is unchanged as it goes through this region, i.e., the proton successfully goes through the entrance slit to the velocity selector and leaves through the exit slit, with both slits along the x-axis, as shown. (c) (2 points) What is the work done by the magnetic field on the proton? (d) (10 points) Now consider the velocity selector from the rest frame of the proton. Since the proton went through the slits in the lab frame, the slits must go around the proton in the proton’s rest frame. Therefore, there must be no force acting on the proton in its rest frame. Show this by using the Lorentz transformation equations
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern