A velocity selector, in which charged particles of a specific speed pass through undeflected while those of greater or lesser speeds are deflected either to the left or to the right. After leaving the velocity selector, particles enter a purely magnetic field. A particle's radius of motion is then used to find the mass-to-charge ratio of the particle, which in turn can identify it. Taken altogether, this device is called a mass spectrometer. The illustrated electric field is directed to the right with magnitude 1.95 times 10^5 V/m and the magnetic field is directed into the screen with magnitude 0.555 T.

a. Determine the speed v of the undeflected charged particle.
b. After passing through the velocity selector, the charged particle moves in a circular path with a radius of r = 6.61 mm. Determine the particle's mass-to-charge ratio. m/q = kg/C