An electron, a proton and a `He^(+)` ion projected into a magnetic field with same kinetic energy, with velocities being perpendicular to the magnetic field. The order of the radii of circles traced by them is :

An electron and a proton enter a magnetic field at right angles to the field with the same kinetic energy

An electron and a proton enter a magnetic field at right angles to the field with the same kinetic energy

A proton and an alpha -particle are projected with the same kinetic energy at right angle to a uniform magnetic field. The ratio of the radii of their paths is

An electron and a proton enter a magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true

A proton and a deuteron with the same initial kinetic energy enter a magnetic field in a a direction perpendicular to the direction of the field . The ratio of the radii of the circular trajectories described by them is

A proton and a deuteron with the same initial kinetic energy enter a magnetic field in a a direction perpendicular to the direction of the field . The ratio of the radii of the circular trajectories described by them is