2015 · Q118
An electron and a proton are circulating with same speed in circular paths of equal radius. Which one among the following will happen, if the mass of a proton is about 2,000 times that of an electron?
General KnowledgePhysics
- AThe centripetal force required by the electron is about 2,000 times more than that required by the proton
- BThe centripetal force required by the proton is about 2,000 times more than that required by the electron
- C) No centripetal force is required for any charged particle
- DEqual centripetal force acts on both the particles as they rotate in the same circular path
Explanation
Centripetal force equals mv²/r. With the same speed and the same radius, the required force scales with mass; the proton's roughly 2,000-times greater mass means it needs about 2,000 times the centripetal force of the electron. The answer is B.