Determine the velocity of a particle in mass spectrometry

In summary, the conversation discusses the determination of the velocity of a particle with mass m coming out of an accelerator. The individual mentions using the equations Ep(i) + Ec(i) = Ep(f) + Ec(f) and Ec(f) = Ec(i) - Ec(f) to calculate the kinetic and potential energy. However, there is confusion about how to express Ep using V and whether a factor of 0.5 should be included. The individual also mentions that the notation used may not be common in English and asks for clarification. The response includes an explanation of the formula for potential energy and suggests understanding the applicability of formulae found. The individual also requests for a diagram to better understand the symbols and formulae used.
  • #1
duchuy
79
3
Homework Statement
V=3000V, B= 0,035 T, m = m = 2.10^(-26) kg, q = e
Relevant Equations
x
Hi, I am trying to determine the velocity of the particle with the mass m coming out of the acclerator.
I tried writing :
Ep(i) + Ec(i) = Ep(f) + Ec(f)
Ec(f) = Ec(i) - Ec(f)
But at this step, I'm no longer sure how to express Ep with V because :
In my textbook, it's written :
Ep = 0,5 (sigma(i) qiVi)
But I am not sure if I am supposed to put that 0,5 in this case or not, which would imply Ep = qV only.

Ep = potential energy
Ec = Kinetic energy
Sorry in advance if these aren't notations that are used in English.

Thank you so much for your help!
 
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  • #2
duchuy said:
Homework Statement:: V=3000V, B= 0,035 T, m = m = 2.10^(-26) kg, q = e
Relevant Equations:: x

Ep = 0,5 (sigma(i) qiVi)
This is true for a collection of charges where the potentials are due to the same charges you are considering. This is to avoid double counting because in actuality the potentials are between pairs of charges. The text you are reading should explain this.

If you are considering a single particle in an external field, then potential energy is U = qV. This is an example of the need to understand formulae that you find and to make sure they are applicable.
 
  • #3
Oh okay thank you sir!
 
  • #4
A diagram would help in understanding what the symbols and the formulae mean.
I am not sure where the second formula
Ec(f) = Ec(i) - Ec(f), comes from.
 

FAQ: Determine the velocity of a particle in mass spectrometry

What is mass spectrometry?

Mass spectrometry is a scientific technique used to determine the molecular weight and chemical composition of a sample. It involves ionizing a sample and then separating the ions based on their mass-to-charge ratio.

How does mass spectrometry determine the velocity of a particle?

Mass spectrometry uses a combination of electric and magnetic fields to accelerate and deflect ions based on their mass-to-charge ratio. The velocity of a particle can then be calculated based on its mass and the strength of the electric and magnetic fields.

Why is determining the velocity of a particle important in mass spectrometry?

The velocity of a particle is important in mass spectrometry because it affects the path and time it takes for the particle to travel through the instrument. This information is used to accurately determine the mass-to-charge ratio and identify the chemical composition of the sample.

What factors can affect the velocity of a particle in mass spectrometry?

The velocity of a particle in mass spectrometry can be affected by the strength of the electric and magnetic fields, the mass-to-charge ratio of the particle, and any collisions or interactions with other particles or molecules in the instrument.

How is the velocity of a particle measured in mass spectrometry?

The velocity of a particle is measured in mass spectrometry by using detectors that can detect the time it takes for the particle to travel through the instrument. This information, along with the known electric and magnetic fields, can then be used to calculate the velocity of the particle.

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