# Mass spectrometer

1. Apr 13, 2010

### Millimole

1. The problem statement, all variables and given/known data

I'm having problem with a couple parts of this problem. I know how to work it (I think), but I'm consistently off by a couple orders of magnitude off the answer provided by the professor.

I've already found that the isotope 90SR+ needs to be given a speed of 25.72*10^4 m/s. This much I know is correct. From there I am asked to find the voltage difference required to accelerate the isotope to this speed.

2. Relevant equations

U=qV
U=.5mv^2

q (elementary charge): 1.602*10^-19 C
m (mass of isotope): 1.495*10^-25 Kg

3. The attempt at a solution

Set the two equations equal to one another. Find the kinetic energy of the isotope traveling at the needed speed. Divide this value by q (charge of a +1 ion). I get the answer 30866.73 V. Professor gets roughly 308 volts. Granted, his answer makes more sense than mine, but I cannot for the life of me find the fault in my work. Note: I calculated the mass of the isotope, but since it yielded the correct answer in a previous question, I assume it is correct. Someone tell me how the hell I'm off by two orders of magnitude?

2. Apr 13, 2010

### Millimole

False alarm everybody. Typing out the problem helped me catch the error. Cheers!

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook