Finding Velocity of Positive ion with Volts given.

[dkr1207]

Homework Statement

An ion is accelerated through potential diff. of 250 V, directly perpendicular to mag. field.
Find radius of the path of the ion in the field.

Given:
mass (m)=2.5 x 10^-26
charge(q)= 1.6 x 10^-19
Volts= 250 V
Mag. Field (B) = 0.50 T

Homework Equations

radius= (mass x VELOCITY)/ (charge x B)

The Attempt at a Solution

I know the answer is 1.77 cm for the radius, but i need to prove how, but i can't seem to find an equation or reason to use Volts to get Velocity in the equation.

 

[Fredrik]

What's the definition of "potential difference"? Thinking about that should help you figure out how to use the number of volts. Hint: energy.

 

[dkr1207]

Pe

First i find PE with:

PE=Volts x charge

plug in to:

velocity=[(-2/mass) x PE]^(1/2)

seems right...

PE= 250V / 1.6 x 10^-19 C = 1.56 x 10^21 J

plug in:
and you get velocity at 3.54 x 10^23 cm/s

but when you use that number in the final radius equation, its not = to 1.77 cm (and i know that's right)

 

[dkr1207]

First i find PE with:

PE=Volts x charge

plug in to:

velocity=[(-2/mass) x PE]^(1/2)

seems right...

PE= 250V / 1.6 x 10^-19 C = 1.56 x 10^21 J

plug in:
and you get velocity at 3.54 x 10^23 cm/s

but when you use that number in the final radius equation, its not = to 1.77 cm (and i know that's right)

 

[dkr1207]

nvm... its good now, thanks for the help