What is the orbital frequency of an electron and positron 2.00nm apart?

In summary, the orbital frequency for an electron and a positron 2.00nm apart can be found by using Newton's law and the formula Fnet = mv^2/r. This leads to an equation with r and v, which can be used to find the period of the orbit. The frequency is then just the reciprocal of the period.
  • #1
imafam
2
0
A positron is an elementary particle identical to an electron except that its charge is . An electron and a positron can rotate about their center of mass as if they were a dumbbell connected by a massless rod. What is the orbital frequency for an electron and a positron 2.00nm apart?

My Approach:
I treated the electron and positron as a system with a torque.
I found that the torque = pEsintheta = qsEsintheta = (1.60*10^-19)(2*10^-9)(1.94*10^9)
but I don't know theta
HELP!
 
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  • #2
Hi imafam,

imafam said:
A positron is an elementary particle identical to an electron except that its charge is . An electron and a positron can rotate about their center of mass as if they were a dumbbell connected by a massless rod. What is the orbital frequency for an electron and a positron 2.00nm apart?

My Approach:
I treated the electron and positron as a system with a torque.
I found that the torque = pEsintheta

This is the formula for the torque on a dipole in an external field E, which is not what you have here.

Instead, think in terms of Newton's law. Draw a force diagram for one of the particles. Also, the particles are going in a circular path; what do you know that is true about circular motion, that you can use here in Newton's law Fnet=ma?
 
  • #3
That Fnet = mv^2/r
alphysicist said:
Hi imafam,



This is the formula for the torque on a dipole in an external field E, which is not what you have here.

Instead, think in terms of Newton's law. Draw a force diagram for one of the particles. Also, the particles are going in a circular path; what do you know that is true about circular motion, that you can use here in Newton's law Fnet=ma?
 
  • #4
imafam said:
That Fnet = mv^2/r

That's right; once you plug in what Fnet is for this case, you'll have an equation with r and v in it.

From that, you can determine the period of the orbit, which is just how long it takes for the particle to go in a complete circle. And then the frequency is just the reciprocal of the period.
 

1. What is an electron and positron?

An electron is a subatomic particle with a negative charge and a mass of approximately 9.11 x 10^-31 kilograms. It is one of the fundamental particles that make up atoms. A positron, on the other hand, is the antiparticle of an electron, meaning it has the same mass but a positive charge.

2. How are electrons and positrons related?

Electrons and positrons are related through the process of annihilation. When an electron and positron collide, they can produce energy in the form of gamma rays or other particles. The total energy of the system (mass and kinetic energy) is conserved during this process.

3. Where can electrons and positrons be found?

Electrons and positrons can be found in many places, including atoms, subatomic particles, and in high-energy environments such as particle accelerators and outer space. They are also created in certain nuclear reactions.

4. What are the uses of electrons and positrons?

Electrons and positrons have many practical uses, including in electronic devices such as televisions and computers. They are also used in medical imaging techniques such as PET scans, and in research to study subatomic particles and the laws of nature.

5. What is the difference between an electron and a positron?

The main difference between an electron and a positron is their charge. An electron has a negative charge, while a positron has a positive charge. They also have opposite spin directions, meaning their magnetic fields point in opposite directions. Additionally, they have different roles in the formation of atoms and their interactions with other particles.

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