Lab 3 - Measuring the Mass-Charge Ratio of Cathode Rays...

This preview shows page 1 - 2 out of 8 pages.

Measuring the Mass-Charge Ratio of Cathode Rays Eric Tao, Andrew Dewhurst February 11st, 2013 Abstract Cathode rays have been observed and studied since antiquity, and here we attempt to quantify the ratio of a cathode ray’s charge with respect to its mass. By using a set starting energy and then balancing the effects of an electrical field acting on the cathode ray against a magnetic field, we were able to determine both the velocity of the cathode ray particles as well as their ratio of charge to mass. 1 Introduction Since the 18th century, people have studied the behavior electricity, especially in low pressure situations. As the technology was more refined, a clear ”beam” started to form, emanating from the cathode and traveling towards the anode. The next logical step was then to test its properties. Through experimentation, it was found that these beams were affected by both electrical and magnetic fields, consistent with that of charged particles. However, measuring the charge to mass ratio of these particles would constitute an insight into their essential character. Using an apparatus that can apply both an electrical field and a magnetic field, we will first observe the qualitative effects of the fields on the beam and then attempt our charge-mass analysis. We note that with the electrical field, the cathode ray was deflected downwards, telling us that the electrical field was pointing upwards, and that the cathode ray has a negative charge associated with it. It leaves the beam as a mostly coherent path, deflecting the particles fairly evenly. A stronger electrical field increases the deflection, while a greater beam voltage decreases the deflection. In addition, it only deflects
Image of page 1

Subscribe to view the full document.

Image of page 2

{[ 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