12. (16 points) A mass spectrometer is used to separate isotopes of different masses. Their charges are known to be +1.60 * 10'19C. The magnetic eld in the velocity selector is set to B=0.530 T so that particles with speed 17 = 1.92 * 106m/ S pass through undeected. After leaving the velocity selector, the particles enter a region where the magnetic eld is B'=3 .67 T. They move in a semicircular path before hitting the particle detector. a) Calculate the magnitude of the electric eld required in the velocity selector. b) If some particles follow a path with radius R1=11.8 cm and others have R2=12.3 cm, nd the respective masses m1 and m2 of these two types of particles. Extra credit: Suppose there is a third particle that weighs l.67*10'27 kg (the mass of one neutron) more than the particle Velocity selector selects particles with speed 0. with mass m2. Where would this particle hit the particle detector relative to the particle with mass m2? Specify the distance (how far from m2) and which side it would land on