question_answer 18)

An electron emitted by a heated cathode and accelerated through a potential difference of 2.0 kV, enters a region with uniform magnetic field of 0.15 T. Determine the trajectory of the electron if the field (a) is transverse to its initial velocity, (b) makes an angle of with the initial velocity.  

Answer:

(a) In this case the trajectory is circular because the magnetic force provides the required centripetal force.                 Using or                 Also or                 i.e.                                 or .                 (b) Here                 Putting the values,                                 In this case electron describes helical path.                 Radius,