Example 1 · difficulty 2/5
A charged particle projected with speed v perpendicular to a uniform magnetic field B moves in a circle of radius r. The experiment is repeated in a field of strength B/2 with the projection speed changed to 2v, everything else remaining the same. The radius of the new circular path is:
- A. r/2
- B. 2r
- C. 4r
- D. r (unchanged)