Final answer:
When a charged particle moves perpendicular to a uniform magnetic field, it follows a curved path in a motion called circular motion. The speed of the charged particle remains constant during this motion. The correct answer is C. A balanced centripetal force; stay the same.
Step-by-step explanation:
When a charged particle moves perpendicular to a uniform magnetic field, it experiences a force that causes it to follow a curved path. This is known as circular motion. The magnetic force acting on the charged particle provides the centripetal force required for the circular motion to occur.
The speed of the charged particle will remain the same during its motion through the magnetic field. The magnetic force only changes the direction of motion, not the magnitude of the velocity.
Therefore, the correct answer is C. A balanced centripetal force; stay the same.