The charge to mass ratio of the electron was first measured by J. J. Thompson in 1897. This is oftenreferred to as THE discovery of the electron. Thompson used a combination of electric and magneticfields in his experiment. We will defer the magnetic part of the experiment to later in the course,and examine the electric part now. The device he used sent a beam of electrons between two plates,as shown below, between two plates. The initial velocity, vo of the beam was horizontally to theright. Thompson then measured the deflection, y, of the beam from where it exited the plates withthe electric field turned off. Thompson also used a magentic field, which allowed him to determinethe initial velocity. For now, lets find an expression for the charge to mass ratio in terms of thisvelocity and the other parameters.yEPlatePlatem₂ Qx = L(a) Assume that the weight of the electron can be neglected, so that the only force in play is theelectric force. Derive an expression (in terms of the given variables E, L, y, and vo) for thisratio of the electron charge to its mass, m/Q showing and explaining all your steps. Hint: thisis very similar to a kinematics/free fall problem, two dimensional motion under the influenceof a constant force, with the constant acceleration a determined by the electric force instead ofgravity. Additional hints are provided in the homework guide at the end of this document.(b) Look up the charge and mass of the electron and design an experiment (choose values for E,L, and vo that give a reasonable deflection y.) We do want to make sure the electric force ismuch larger than the gravitational force on the electron. Note that electron velocities can bevery close to the speed of light, since the electron mass is so very small.

Given:length of the plates, Ldeflection of beam during exit, yinitial velocity of the electrons, vo…

The charge to mass ratio of the electron was first measured by J. J. Thompson in 1897. This is often referred to as THE discovery of the electron. Thompson used a combination of electric and magnetic fields in his experiment. We will defer the magnetic part of the experiment to later in the course, and examine the electric part now. The device he used sent a beam of electrons between two plates, as shown below, between two plates. The initial velocity, vo of the beam was horizontally to the right. Thompson then measured the deflection, y, of the beam from where it exited the plates with the electric field turned off. Thompson also used a magentic field, which allowed him to determine the initial velocity. For now, lets find an expression for the charge to mass ratio in terms of this velocity and the other parameters.

The charge to mass ratio of the electron was first measured by J. J. Thompson in 1897. This is often referred to as THE discovery of the electron. Thompson used a combination of electric and magnetic fields in his experiment. We will defer the magnetic part of the experiment to later in the course, and examine the electric part now. The device he used sent a beam of electrons between two plates, as shown below, between two plates. The initial velocity, vo of the beam was horizontally to the right. Thompson then measured the deflection, y, of the beam from where it exited the plates with the electric field turned off. Thompson also used a magentic field, which allowed him to determine the initial velocity. For now, lets find an expression for the charge to mass ratio in terms of this velocity and the other parameters.

Inquiry into Physics

8th Edition

ISBN:9781337515863

Author:Ostdiek

Publisher:Ostdiek

Chapter8: Electromagnetism And Em Waves

Section: Chapter Questions

Problem 9Q

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