Prove this equation using fields: show F=Bqv

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In summary, the equations F=BIl and I=nAqv can be used to show that F=Bqv, where B is the magnetic field, q is the charge, v is the velocity, and n is the number of charges per unit volume. The number of charges in a length L of wire with cross-section area A can be calculated as N=nAL.
  • #1
GCSEsoon
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Homework Statement


Use equations F=BIl I=nAqv show F=Bqv, (help: the no. of particlees in a length l of wire cross-section area A is nAl, when the no. of particlees per unit volume is n)

Homework Equations


F=BIl I=nAqv F=Bqv

The Attempt at a Solution



F=B(nAqv)l
F=B(nnAlqv)l
F=B(n2Al2qv
F=B(n2Al2Itl/t
F=B(n2Al2Il
F=B(n2Al3I

I'm stuck after this, help asap appreciated.
 
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  • #2
It is quite hard to distinguish small L from big i, fixed it below:

Given:
F=BIL
I=nAqv this should read NAqv where N is the total number of charges
number of charges N in a length L of wire cross-section area A is N = nAL, when the number of charges per unit volume is n

Can you give it another try now?
 
  • #3
drmalawi said:
Can you give it another try now?
I wouldn't put too much hope about now. This decade, maybe.
 
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Likes nasu and malawi_glenn

1. How do you prove the equation F = Bqv using fields?

To prove this equation, we can start by defining the variables: F represents the force on a charged particle, B is the magnetic field, q is the charge of the particle, and v is its velocity. We can then use the equation F = qv x B, where x represents the cross product. This equation shows that the force on a charged particle is perpendicular to both its velocity and the magnetic field, and its magnitude is proportional to the charge, velocity, and strength of the magnetic field.

2. What is the importance of this equation in the field of physics?

This equation is important because it helps us understand the relationship between charged particles and magnetic fields. It is also useful in explaining the behavior of particles in electromagnetic fields, which is crucial in many areas of physics, including electricity, magnetism, and electronics.

3. Can you provide an example of how this equation is used in real-life situations?

Sure, one example is the operation of a cathode ray tube (CRT) television. The electron gun in a CRT uses a magnetic field to steer the electrons towards the screen, while the voltage applied to the electron beam controls its speed. The equation F = Bqv helps us understand how these factors affect the trajectory of the electrons and produce the image on the screen.

4. Are there any limitations to this equation?

Yes, this equation only applies to charged particles moving in a magnetic field. It does not take into account other forces or factors that may affect the motion of the particles. Additionally, it only applies to non-relativistic speeds, meaning it is not accurate for particles moving at speeds close to the speed of light.

5. How can this equation be derived from other fundamental equations in physics?

This equation can be derived from the Lorentz force law, which states that the force on a charged particle in an electromagnetic field is equal to the product of its charge, velocity, and the cross product of the electric and magnetic fields. By substituting the electric field with the equation for electric force, we can arrive at the equation F = qv x B.

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