29. (a) If vis the speed of the positron then vsin φis the component of its velocity in the plane that is perpendicular to the magnetic field. Here is the angle between the velocity and the field (89°). Newton’s second law yields eBvsin = me(vsin )2/r, where ris the radius of the orbit. Thus r= (mev/eB) sin . The period is given by ( )()31101929.1110kg223.58 10s.sin1.60 10C 0.100TemrTveB−−−π×ππ====××The equation for ris substituted to obtain the second expression for T. (b) The pitch is the distance traveled along the line of the magnetic field in a time interval
This is the end of the preview. Sign up
access the rest of the document.