Electric potential difference to accelerate electron

[jegues]

Homework Statement

What electric potential difference is required to accelerate and electron, initially at rest, to the speed at which it will move in a circular path with radius 1cm when the electron enters a region of uniform magnetic field of 1.0T, if the field is perpendicular to the electron's velocity? (Ignore gravity)

Homework Equations

The Attempt at a Solution

We know that,

[tex]F_{B} = qvB = \frac{mv^{2}}{r}[/tex]

So,

[tex]v = \frac{qBr}{m}[/tex]

The part I'm confused about is how to relate this knowledge the the potential difference?

Any suggestions?

EDIT: I figured it out.

[tex]\Delta V = \frac{qB^{2}r^{2}}{2m}[/tex]

 

[cupid.callin]

change in the potential energy is equal to gain in kinetic energy

qV = 0.5mv²