Charged Particles in Magnetic Fields

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Homework Help Overview

The discussion revolves around the behavior of charged particles, specifically an ionized deuteron, in the context of a velocity selector involving electric and magnetic fields. The problem involves calculating the speed of the particle given specific field strengths.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the forces acting on charged particles in electric and magnetic fields, referencing the equations F = qE and F = qvB. There is an exploration of the relationship between electric and magnetic fields in determining the velocity of charged particles.

Discussion Status

Some participants have attempted to derive the speed of the charged particle using the relationship V = E/B, while others question the validity of multiplying the electric and magnetic field strengths directly. There is an ongoing examination of the correct approach to finding the velocity, with multiple interpretations of the equations presented.

Contextual Notes

There are concerns regarding the accuracy of the values used for the electric and magnetic fields, as well as the method of calculation. Participants are also addressing issues related to the presentation of information and the importance of original explanations.

predentalgirl1
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1. An ionized deuteron (a particle with a + e charge) passes through a velocity selector whose perpendicular magnetic and electric fields have magnitudes of 40 mT and 8.0 kV/m, respectively. Find the speed of the ion



2. When a charge particle moves in a velocity selector, both electric field and magnetic field are there.

Any charged particle in an electric field will feel a force proportional to the charge and field strength such that F = qE , where F is force, q is charge, and E is electric field. Similarly, any particle moving in a magnetic field will feel a force proportional to the velocity and charge of the particle. The force felt by any particle is then equal to F = qv X B , where F is force, q is the charge on the particle, v is the velocity of the particle, B is the strength of the magnetic field, and X is the cross product. In the case of a velocity selector, the magnetic field is always at 90 degrees to the velocity and the force is simplified to F = qvB in the direction described be the cross product.

F = qE and F = qvB

So, qE = qvB

V = E/B

Setting the two forces to equal magnitude in opposite directions it can be shown that V = E/B . Which means that any combination of electric (E) and magnetic (B) fields will allowed charged particles with only velocity (v) through.





3. E = 8 KV/m = 8 x 103 V/m

B = 40 mT = 40 x 10-3 T

V = 8 x 103 x 40 x 10-3

V = 320 m/sec

(Ans)

 
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predentalgirl1 said:
Any charged particle in an electric field will feel a force proportional to the charge and field strength such that F = qE , where F is force, q is charge, and E is electric field. Similarly, any particle moving in a magnetic field will feel a force proportional to the velocity and charge of the particle. The force felt by any particle is then equal to F = qv X B , where F is force, q is the charge on the particle, v is the velocity of the particle, B is the strength of the magnetic field, and X is the cross product. In the case of a velocity selector, the magnetic field is always at 90 degrees to the velocity and the force is simplified to F = qvB in the direction described be the cross product.

F = qE and F = qvB

So, qE = qvB

V = E/B

Setting the two forces to equal magnitude in opposite directions it can be shown that V = E/B . Which means that any combination of electric (E) and magnetic (B) fields will allowed charged particles with only velocity (v) through.





3. E = 8 KV/m = 8 x 103 V/m

B = 40 mT = 40 x 10-3 T

V = 8 x 103 x 40 x 10-3

V = 320 m/sec

(Ans)


Why have you multiplied E and B?

(I really don't feel that you should copy and paste almost the entire page from Wikipedia, along with the grammatical and spelling mistakes. Write it yourself.)
 
Shooting star said:
Why have you multiplied E and B?

(I really don't feel that you should copy and paste almost the entire page from Wikipedia, along with the grammatical and spelling mistakes. Write it yourself.)


If I should not multiply E and B, what
should I do instead to get the correct answer?
 
predentalgirl1 said:

F = qE and F = qvB

So, qE = qvB

V = E/B

This is from your post. What do you think you should do to get v?
 
Given that B =40 x 10 ^-6
E = 8000 V/m

have Bev = eE

v = E/B

v= 8000/ 40 x 10^-6
v= 2 x 10^8m/s
 
predentalgirl1 said:
Given that B =40 x 10 ^-6
Is the value of B you have used here is correct?
 

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