A particle of charge , mass , and kinetic energy enters in a magnetic field perpendicular to its velocity and undergoes a circular arc of radius . Which of the following curves represents the variation of with ?
- A
(1) a straight line through the origin, so that grows in direct proportion to
- B
(2) a curve through the origin whose slope keeps increasing, so that grows faster and faster with
- C
(3) a curve that starts high and falls off, so that decreases as increases
- D
(4) a curve through the origin whose slope keeps decreasing, so that grows but flattens out as increases