- #1

pollytheparrot

- 11

- 0

## Homework Statement

Basically there are 3 plate capacitors, with a distance a between the first two and b between the last two. In between the first two plates is voltage V. A particle of charge q is released from the first plate, and when it leaves the second plate it is no longer accelerating. There is a magnetic field of B in the second part, and then a hole of radius r at the third plate, find the distance that the particle drops due to the magnetic field. I neglected to outline this specifically in the picture, but basically it is the distance of the bottom black line and could be called "d"

## Homework Equations

U=K

F=qv x B

Sum F = ma

a=v^2/r

E=qV

## The Attempt at a Solution

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First I had to find the velocity of the particle at the point of the first plate, and did this using conservation of energy.

U=K

qV=.5mv^2

v=sqrt(2qV/m)

Second, is finding the radius of the circle in the second part, using F=ma and angular acceleration

Then Sum F = ma, only force is magnetic

qv x B = ma

qv x B = m(v^2/R)

R=m*v^2 / q*v*B

R=m*(2qV/m) / q*B*sqrt(2qV/m)

R=2V/Bsqrt(2qV/m)

At this point I have the radius R of the circular path that the magnetic field induces, but I'm totally lost at this point. I'm assuming it's just geometry of some fashion. Really would appreciate help.