An electron starts at rest and is accelerated through a constant potential difference of 1200 V. Then, the electron V B immediately enters a region of uniform magnetic field with -e a magnitude of B = 0.25 T, which is perpendicular to the electron's motion. The electron travels in a half-circle in the L magnetic field, before crashing into a wall. R a. Find the electron's speed before it enters the magnetic field. (Hint: consider energy conservation). [2 marks] b. Calculate the magnitude of the Lorentz force on the particle. [2 marks] c. Determine the radius of the half-circle. [2 marks] d. Calculate the time it takes to crash into the wall. (Hint: consider the period of the circular orbit). [1 mark]