Finding Current in a Long Solenoid

[missyc8]

Homework Statement

A long solenoid has 100 turns/cm and carries current i. An electron moves within the solenoid in a circle of radius 2.20 cm perpendicular to the solenoid axis. The speed of the electron is 0.048 c (c = speed of light). Find the current i in the solenoid.

Homework Equations

i= mv/e*mu*n*r

The Attempt at a Solution

i= (9.11E-31kg)(.0480)(3.0E8)/ (1.6E-10 C)(4*pi E-7 Tm/A)(100/.01 m) (2.2E-2) = .266 A
this answer is wrong...
what am i doing wrong? thank you!

 

[Delphi51]

Probably a typo but you wrote 1.6E-10 for the charge on the electron.
Of course you need brackets around all the factors in the denominator.
I ran your calc through my calculator and got .297 A.

 

[missyc8]

yeah, that's right! i must have messed up on the calculations somewhere!