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1. At some instant an electron is moving in the plane of thispage. The speed is

ID: 1748703 • Letter: 1

Question

1. At some instant an electron is moving in the plane of thispage. The speed is 2 x10^6 m/s. There is a uniform magnetic fieldof 1.4 Tesla pointing from the bottom of the page to the top. Thereis a force of 1.6x10^-13 newtons acting on the electron pointingout of the page. a) What direction is the electron moving? b) Is there more than one possible direction? c) What would be the force if the electron were movingperpendicular to the force? 1. At some instant an electron is moving in the plane of thispage. The speed is 2 x10^6 m/s. There is a uniform magnetic fieldof 1.4 Tesla pointing from the bottom of the page to the top. Thereis a force of 1.6x10^-13 newtons acting on the electron pointingout of the page. a) What direction is the electron moving? b) Is there more than one possible direction? c) What would be the force if the electron were movingperpendicular to the force?

Explanation / Answer

We know that :           Forcein the magnetic field is :                        F   = B q v sin                  sin = F / B q v                              = 1.6 x 10-13 / ( 1.4 * 1.602 x 10-19 *2 x 106 )                             =   0.35669 Hence direction = sin-1(  0.35669 )                             =   20.89o (b)        There is only onepossible direction. (c)         If theelectron were moving perpendicular to the field :                     F   = B q v sin90                           = B q v                            = 1.4 * 1.602 x 10-19 * 2 x106                          = 4.485 x 10-13 N Hope this helps u!