Determine the velocity of a particle in mass spectrometry

AI Thread Summary
To determine the velocity of a particle in mass spectrometry, the relationship between potential energy (Ep) and kinetic energy (Ec) must be correctly applied. The equation Ep = 0.5 (sigma(i) qiVi) is valid for multiple charges, while for a single particle in an external field, Ep simplifies to U = qV. This distinction is crucial to avoid misapplication of the formulas. Clarification is needed on the origin of the equation Ec(f) = Ec(i) - Ec(f), as it appears to be incorrectly stated. Understanding the context and correct application of these equations is essential for accurate calculations.
duchuy
Messages
79
Reaction score
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!
 
Physics news on Phys.org
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.
 
Oh okay thank you sir!
 
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.
 
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Trying to understand the logic behind adding vectors with an angle between them'
My initial calculation was to subtract V1 from V2 to show that from the perspective of the second aircraft the first one is -300km/h. So i checked with ChatGPT and it said I cant just subtract them because I have an angle between them. So I dont understand the reasoning of it. Like why should a velocity be dependent on an angle? I was thinking about how it would look like if the planes where parallel to each other, and then how it look like if one is turning away and I dont see it. Since...
Back
Top