Charged particles of mass m = 1 1026 kg and charge q = 1 1018 C are initially stationary in a source S. They accelerate through plates A and B, which have a potential difference of (VA VB ), and emerge with a speed = 1 106 m/s. The charges then pass through a velocity selector, which consists of two parallel plates P 1 and P 2 between which an unspecified uniform electric field exists and also contains a uniform magnetic field B = 0.50 T (directed out of the page). The charges pass through the velocity selector without any change in their speed or direction. The particles then enter a region of uniform magnetic field B = 0.50 T directed into the page. At the point of entry, the velocity vector makes an angle = 60 with the B-field boundary as shown. (a) What is the potential difference VA VB ? [3 marks] (b) What is the magnitude and direction of the electric field between P1 and P 2