Circle motion of a charge refers to the circular path that a charged particle follows when it is subjected to a magnetic field. This is caused by the Lorentz force, which acts perpendicular to the particle's velocity and the magnetic field.
The equation is given by r = mv/qB, where r is the radius, m is the mass of the particle, v is its velocity, q is its charge, and B is the strength of the magnetic field.
If the magnetic field strength is increased, the radius of the circular motion will decrease. This is because the Lorentz force is directly proportional to the magnetic field strength, so a stronger field will cause a greater force and a tighter circular path.
No, a charged particle cannot have circular motion without a magnetic field. The Lorentz force is necessary to create the circular path, and without a magnetic field, there is no force acting on the particle perpendicular to its velocity.
The charge of the particle does not affect the radius of its circular motion, but it does affect the speed. A particle with a greater charge will experience a greater Lorentz force, causing it to move faster in its circular path.