Question

When a charged particle enters a magnetic field traveling so that its velocity vector is perpendicular to the magnetic field, B, then its path will be

Answer 1

The direction of force is given by right hand rule. For a positive charge, with velocity along rightwards on the paper, magnetic field along into the paper, the direction of magnetic force is along upwards. So, the force will tend to change the direction of motion finally along the force, but again in this condition, the direction will be mutually perpendicular to both velocity and field. and hence it will keep changing the direction of motion, finally making the path circular. So, When a charged particle enters a magnetic field traveling so that its velocity vector is perpendicular to the magnetic field, B, then its path will be circular.