The magnetic force on a charged particle is always perpendicular to its velocity. Can the magnetic force change the velocity of the particle?Speed of the particle?

A charged particle is moved along a magnetic field line. The magnetic force on the particle is

A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle . The motion of the particle takes palace in a plane , it follow that

A particle is acted upon by a force of constant magnitude which is always is perpendicular to the velocity of the particle , the motion of the particles takes place is a plane it follow that

Which of the following statement(s) is/are correct? If a charged particle moves In a region of magnetic field such that velocity of charged particle v is perpendicular to magnetic field B, then trajectory of the particle is a circle. II. Force acting on the charged particle is q (vxxB).