Q.

A particle of charge q, mass m and kinetic energy E enters in magnetic field perpendicular to its velocity and undergoes a circular arc of radius (r). Which of the following curves represents the variation of r with E          [2025]

1  
2  
3  
4  

Ans.

(4)

12mv2=E  (mv)2=2mE

Also, r=mvqB  r=2mEqB

So, r(E)12

Graph should be like