An electron (charge q = -1.6x10-19 C and mass m = 9.1x10-31) moving at speed v enters a region where a uniform magnetic field B = 1.9 × 10-4 T bends the path of the electron into a semicircle with radius of r = 3.5 cm as shown.
(a) What is the speed of the electron as it enters the region of non-zero magnetic field?
(b) What is the speed of the electron as it leaves the region of non-zero magnetic field?
(c) How much work was done on the electron by the magnetic field in this region?