Magnetic Force

In the presence of magnetic field ?B? and electric field ?E?, the total force on a moving charged particle is

A rectangular loop carrying a current is placed in a uniform magnetic field . The area enclosed by the loop is . If there are turns in the loop, the torque acting on the loop is given by

An electron of mass under the action of a magnetic field moves in a circle of radius at a speed of . If a proton of mass was to move in a circle of same radius in the same magnetic field, then its speed will become

An electron of mass kg under the action of a magnetic field moves in a circle of radius 2 cm at a speed of m/s. A proton of mass kg moves in a circle of same radius in the same magnetic field, then its speed will become