If a proton is projected in a direction perpendicular to a uniform magnetic field with velocity v and an electron is projected along the lines of force, what will happen to proton and electron [DPMT 1979]

• A.            The electron will travel along a circle with constant speed and the proton will move along a straight line
• B.            Proton will move in a circle with constant speed and there will be no effect on the motion of electron
• C.            There will not be any effect on the motion of electron and proton
• D.            The electron and proton both will follow the path of a parabola