The particle will experience a force perpendicular to the direction of its velocity which will result in circular motion
The charge is moving at right angles to the magnetic field. It will experience a force of magnitude:
Where B is the strength of the field,
The direction of this force will be perpendicular to the direction of the velocity (you can use Fleming's left hand rule to give you the direction in this case). Hence this force will result in the object moving in a circular path.