What is the Magnetic Field Strength of a Magnetron at a Resonant Frequency?

In summary, the conversation discusses the calculation of the magnetic field strength in a magnetron, given the resonant frequency and period of revolution of the electrons. The equation used is f=qv*b, with q representing the charge, v representing the velocity, and b representing the magnetic field. The additional equation needed is the calculation of speed based on the time it takes to go around a circle, which leads to the solution for the magnetic field strength.
  • #1
Hellphish
2
0

Homework Statement



A magnetron is a microwave source in which a "bunch" of electrons travel on a circular orbit in a uniform magnetic field. As the electrons pass the electrodes, a high-frequency alternating voltage difference occurs. Suppose the resonant frequency is f = 2.82×10^10 s-1; that is, the electron period of revolution is T = 3.55×10^-11 s. What is the corresponding strength of the magnetic field?
The electron charge is -1.6E-19 C and the electron mass is 9.1E-31 kg.

Homework Equations



f=qv * b
where q is the charge, v is the velocity, and b is the magnetic field

The Attempt at a Solution



I think I need to set a centripetal force equal to the magnetic force. The only equation I know for centripetal force is f=m(v^2 / r) and I'm not sure how to solve that with the period. I'm really just not sure if I'm even going about this right or how I can solve for v and r. Any help would be appreciated.
 
Physics news on Phys.org
  • #2
Hellphish said:

Homework Statement



A magnetron is a microwave source in which a "bunch" of electrons travel on a circular orbit in a uniform magnetic field. As the electrons pass the electrodes, a high-frequency alternating voltage difference occurs. Suppose the resonant frequency is f = 2.82×10^10 s-1; that is, the electron period of revolution is T = 3.55×10^-11 s. What is the corresponding strength of the magnetic field?
The electron charge is -1.6E-19 C and the electron mass is 9.1E-31 kg.

Homework Equations



f=qv * b
where q is the charge, v is the velocity, and b is the magnetic field

The Attempt at a Solution



I think I need to set a centripetal force equal to the magnetic force. The only equation I know for centripetal force is f=m(v^2 / r) and I'm not sure how to solve that with the period. I'm really just not sure if I'm even going about this right or how I can solve for v and r. Any help would be appreciated.

You are only missing one equation (which is quite simple). Consider a particel going in a circle of radius r. If it takes a time T to go around once, what is the speed of the particle?
 
  • #3
Oh wow, I didn't even think of that. Thanks.
 

What is magnetic field strength?

Magnetic field strength is a measure of the intensity of a magnetic field. It is a vector quantity, meaning it has both magnitude and direction.

How is magnetic field strength measured?

Magnetic field strength is typically measured using a device called a magnetometer. This device can detect the strength and direction of a magnetic field at a specific location.

What factors affect magnetic field strength?

The strength of a magnetic field is affected by the distance from the source of the field, the size and shape of the magnetic source, and the magnetic properties of the material the field is passing through.

What units are used to measure magnetic field strength?

Magnetic field strength is measured in units called teslas (T) or gauss (G). One tesla is equal to 10,000 gauss.

Why is magnetic field strength important?

Magnetic field strength plays a crucial role in many aspects of modern technology, including electricity generation, telecommunications, and medical imaging. It also has a significant impact on the behavior of charged particles in space and can affect the Earth's climate and weather patterns.

Similar threads

Replies
49
Views
3K
  • Introductory Physics Homework Help
Replies
4
Views
270
  • Introductory Physics Homework Help
Replies
6
Views
712
  • Introductory Physics Homework Help
Replies
31
Views
971
  • Introductory Physics Homework Help
Replies
7
Views
783
  • Introductory Physics Homework Help
Replies
11
Views
1K
  • Introductory Physics Homework Help
Replies
12
Views
52
  • Introductory Physics Homework Help
Replies
23
Views
2K
  • Introductory Physics Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
13
Views
2K
Back
Top