A beam of protons is directed in a straight line along the positive-z direction through a region of space in which there are crossed electric and magnetic fields. If the electric field magnitude is E = 430 V/m in the negative-y direction and the protons move at a constant speed of v = 1.7 x 105 m/s. Determine the direction and magnitude B of the magnetic field B that ensures that the beam of protons continues undeflected along its straight-line trajectory. Direction of B: +x O+y O+z -X -y O-z B = T