a NICE ONE....

dude is dis frm resnick????

blood seems to be in a hurry.....
my ans is 1.33m/s
polarity will depend on charge type...

a)The positive charge will be deflected towards pt A and negative
towards pt. B due to magnetic force.
This produces electric field from pt A to B.

At equilibrium,
F_m=F_e
so, Bqv=q(V/d)
so, v=V/Bd=160 * 10 ^-6/(0.04)(3 *10 ^-3)=1.3 m/s

b)The sign of potential diff would not depend upon charge of ions.
BECAUSE negative ions moving in direction of v would be deflected
towards B due to which higher potential at A.Even if positive charge
in direction of v are deflected towards A then also A has higher
potential.

THIS IS THE ANS....

Thats what I have written dear..........

eureka u r right....

thnx u all