Mass spectrometer problem -- Need help

In summary: The particle has a charge of +e. The electric field in the velocity selector acts on the particle with a force of 1.6x10^-19 C.
  • #1
Ryan Gibbons
2
0

Homework Statement



A mass spectrometer is constructed using a velocity selector constructed using a parallel plate capacacitor in a uniform magnetic field Bin. The electric field in the selector is 1003.9 V/m and the magnetic field in that portion of the spectrometer is Bin = 0.998 T. The balanced forces only allow specific velocities through the selector.

http://misterfig.org/pluginfile.php/1936/question/questiontext/8281/18/123907/spect.jpg
The mass of the ions can be found by measuring the radius of the motion when the ions strike point P.
The magnetic field in the circular motion chamber is Bout = 0.807 T.
What is the radius (in millimeters) for an ion of mass 2.66 x 10-26 kg and a charge of +e (1.60 x 10-19 C) ?

Homework Equations


Fm=Fe
BQV=MV^2/R
VQ=MV^2/2

The Attempt at a Solution


VQ=MV^2/2
V=2Q/M= 12030075.19 m/s

BQV=MV^2/R
R=MV/BQ=2.48 m
This is not the correct solution but i cannot figure out how to find the correct one. Please help. Thanks
 
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  • #2
Ryan Gibbons said:

Homework Statement



A mass spectrometer is constructed using a velocity selector constructed using a parallel plate capacacitor in a uniform magnetic field Bin. The electric field in the selector is 1003.9 V/m and the magnetic field in that portion of the spectrometer is Bin = 0.998 T. The balanced forces only allow specific velocities through the selector.

http://misterfig.org/pluginfile.php/1936/question/questiontext/8281/18/123907/spect.jpg
The mass of the ions can be found by measuring the radius of the motion when the ions strike point P.
The magnetic field in the circular motion chamber is Bout = 0.807 T.
What is the radius (in millimeters) for an ion of mass 2.66 x 10-26 kg and a charge of +e (1.60 x 10-19 C) ?

Homework Equations


Fm=Fe
BQV=MV^2/R
VQ=MV^2/2

The Attempt at a Solution


VQ=MV^2/2
V=2Q/M= 12030075.19 m/s

You apply the wrong formula. What is the electric force on the particle?
Ryan Gibbons said:
BQV=MV^2/R
R=MV/BQ=2.48 m
This is not the correct solution but i cannot figure out how to find the correct one. Please help. Thanks
 
  • #3
the electric force on the particle is 1.6x10^-19 C
 
  • #4
Ryan Gibbons said:
the electric force on the particle is 1.6x10^-19 C
No, it is the charge of the particle. What force acts on it due to the electric field of the velocity selector?
 

FAQ: Mass spectrometer problem -- Need help

What is a mass spectrometer and how does it work?

A mass spectrometer is a scientific instrument used to measure the mass-to-charge ratio of particles. It works by ionizing a sample, separating the ions based on their mass-to-charge ratio, and then detecting and measuring the ions to create a mass spectrum.

What are the common problems associated with mass spectrometers?

Some common problems with mass spectrometers include contamination of samples, instrument malfunctions, and incorrect calibration of the instrument.

How can I troubleshoot a problem with my mass spectrometer?

The first step in troubleshooting a problem with a mass spectrometer is to carefully check all components and connections for any visible issues or damage. It is also helpful to run control samples and compare the results to previous data to identify any discrepancies. If the issue persists, it may be necessary to consult the instrument manual or seek assistance from a specialist.

What are some potential sources of error in mass spectrometry data?

Some potential sources of error in mass spectrometry data include contamination of samples, instrument malfunctions, incorrect calibration, and human error during data analysis.

How can I improve the accuracy and precision of my mass spectrometry data?

To improve the accuracy and precision of mass spectrometry data, it is important to properly prepare samples, maintain the instrument, and regularly calibrate and standardize the equipment. Additionally, careful data analysis and comparison to control samples can help identify and correct any errors or discrepancies in the data.

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