In the figure below, an electron with an initial kinetic energy of 3.0 keV enter
ID: 1905570 • Letter: I
Question
In the figure below, an electron with an initial kinetic energy of 3.0 keV enters region 1 at time t = 0. That region contains a uniform magnetic field directed into the page, with magnitude 0.010 T. The electron goes through a half-circle and then exits region 1, headed toward region 2 across a gap of 21.0 cm. There is an electric potential difference ?V = 2400 V across the gap, with a polarity such that the electron's speed increases uniformly as it traverses the gap. Region 2 contains a uniform magnetic field directed out of the page, with magnitude 0.020 T. The electron goes through a half-circle and then leaves region 2. At what time t does it leave? http://www.webassign.net/hrw/hrw7_28-38.gifExplanation / Answer
In the figure, an electron with an initial kinetic energy of4.00 keV enters region 1 at time t = 0. That regioncontains a uniform magnetic field directed into the page, withmagnitude 0.00590 T. The electron goes through a half-circle andthen exits region 1, headed toward region 2 across a gap of 21.0cm. There is an electric potential difference V = 2000 Vacross the gap, with a polarity such that the electron’sspeed increases uniformly as it traverses the gap. Region 2contains a uniform ma
Radius oforbit = r = mv/qBSince Kinetic Energy K = (1/2)mv2v = (2K/m)..............................(1) r = m(2K/m)/qB = (2Km) / qB.....................(2)K = 4 x 103 eV = 4 x 103 x 1.6 x10-19 J = 6.4 x 10-16 JPlug values into (1)v = (2 x 6.4 x 10-16 / 9.1 x 10-31) =3.75 x 107 m/sr = mv/qB = 3.6 x 10-2 m in Region 1 = 1.01 x 10-2 m in Region 2Circling Period T = 2r/v = 6.02 x 10-9 s in region1Between the regions , there is a PD of 2 kV,