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 = 450 V/m in the negative y-direction and the protons move at a constant speed of v = 4.3 x 105 m/s, what must the direction and magnitude of the magnetic field be in order for the beam of protons to continue undeflected along its straight-line trajectory? Select the direction of the magnetic field B. negative z-direction negative y-direction positive x-direction positive z-direction negative x-direction positive y-direction magnitude of the magnetic field B: 1.0465 x10 0-3 T Determine the direction of the force that will act on the charge in each of the following situations. A positive charge moving to the right in a magnetic field that points into the screen. A positive charge moving to the left in an electric field that points out of the screen. A negative charge moving to the right in a magnetic field that points to the right. upward downward zero force Answer Bank into the screen out of the screen to the right to the left