# Cyclotron Frequency problem

1. Sep 6, 2007

### boozi

1. The problem statement, all variables and given/known data
What is the cyclotron frequency in a 3.10 T magnetic field of the ions listed below? The masses of the atoms are shown in the table. The accuracy of your answers should reflect the accuracy of the data given below. (Although N2+ and CO+ both have a nominal molecular mass of 28, they are easily distinguished by virtue of their different cyclotron resonance frequencies.)

(a) N2+ ______ MHz
(b) O2+ ______ MHz
(c) CO+ ______ MHz

B = 3.10 T
2 Oxygen molecules positively ionized (+1) = 2 * 15.9949 u * 1.661*10^-27 = 5.31*10^-26kg

2 Nitrogen molecules positively ionized (+1) = 2 * 14.0031 u * 1.661*10^-27 =
4.6518*10^-26kg

Carbon monoxide positively ionized (+1) = 12.0000 + 15.9949 u * 1.661*10^-27 =
4.64995*10^-26kg
2. Relevant equations
frequency = (qB)/(2pi*m)

3. The attempt at a solution
Well, I've calculated the result so many times, and for some reason, it gives me the wrong answer..... I'm supposed to end up with MHz, so what I've done was plug in all the "supposedly" correct numbers, which are the following:
q = 1.602*10^-19C
B = 3.10 T
m = The mass of the molecule - the mass of one electron.
Can anyone tell me why I'm wrong? Here are my answers:
N2+ 1.6991 MHz
O2+ 1.4875 MHz
CO+ 1.6998 MHz