Figure shown circular region of radius `R = sqrt(3)m` in which upper half has uniform magnetic field `vec(B)=0.2(-hat(K))T` and lower half has uniform magnitic field `vec(B)=0.2hat(K)T`. A very thin parallel beam of point charges each having mass m = 2gm, speed `v = 0.3m//sec` and charge `q= +1mC` are projected along the diameter as shown in figure. A screen is placed perpendicular to initial velocity of charges as shown. If the distance between the point on screen where charges will strike is 4X meters, then calculate X.

Explanation

Required `d=4R tan 60^@=4(sqrt3)sqrt3=12`