An electron and proton enter a uniform magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true?

An electron and proton enter a uniform magnetic field perpendicularly.

1.	An electron and proton enter a uniform magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true?
Answer» Trajectory of electron is less curved Trajectory of proton is less curved Both TRAJECTORIES are equally curved Both move on STRAIGHT line path Solution :Whena charged particles enters a magnetic field perpendicularly, it moves on a circular path. The required centripetal force is provided by magnetic force or `qvB=(mv^(2))/r :. r=(mv)/(QB)` Now kinetic ENERGY of the PARTICLE, `K=1/2 mv^(2)rArr mv=sqrt(2mK)` Therefore, Eq(i) becomes `r=(sqrt(2mK))/(qB)` or `r prop sqrt(m)` `:. (r_(e))/(e_(p))=sqrt((m_(e))/(m_(p)))` As `m_(e) lt m_(p)` so, `r_(e) lt r_(p)` Hence , trajectory of proton is less curved.