7a: An electron has an instantaneous velocity of (106+2 x 102) m/s. It is in a region of the Earth's magnetic field where the magnetic field is approximately constant. Assume that B 1x 10- T. Determine the number of orbits the electron completes while it travels 1000 m in the z-direction b: Repeat part a if the particle was a proton c: Are we justified in ignoring the gravitational field of the Earth here? Explain/calculate.