Alpha Particle Flow: Current & Resistance

In summary, the problem involves a steady beam of alpha particles with a charge of +2e and a constant kinetic energy of 20MeV, carrying a current of 0.25 micro ampere. The questions ask how many alpha particles strike a surface in a given time, the number of particles in a certain length of the beam, and the potential difference needed to accelerate each particle to 20MeV. The solution involves using the definition of an ampere and the formula E = Vq.
  • #1
xerox2ooo
8
0
Can anyone give some hints on this problem?
This is about current and resistance.

Problem: A steady beam of alpha particles (q= +2e) traveling with constant kinetic energy 20MeV carries a current of 0.25 micro ampere.
(a) If the beam is directed perpendicular to a plane surfece, how many alpha particlees strike the surface in 3.0s?
(b) At any instant, how many alpha particles are there in a given 20 cm length of the beam?
(c) Through what potential difference was it necessary to accelearte each alpha particle from rest to bring it to an energy of 20 MeV?

Thanks,
 
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  • #2
Originally posted by xerox2ooo
Problem: A steady beam of alpha particles (q= +2e) traveling with constant kinetic energy 20MeV carries a current of 0.25 micro ampere.
(a) If the beam is directed perpendicular to a plane surfece, how many alpha particlees strike the surface in 3.0s?
Remember what an ampere is? That's coulombs per second. Just start multiplying stuff until the units work out the way you want them to.

[tex](\frac{coulomb}{second})(seconds)(\frac{\alpha}{coulomb})[/tex]

coulombs and seconds will cancel out and you're left with the number of alpha particles.

(b) At any instant, how many alpha particles are there in a given 20 cm length of the beam?
This one I don't know.

(c) Through what potential difference was it necessary to accelearte each alpha particle from rest to bring it to an energy of 20 MeV?

[tex]E = Vq[/tex]

[tex]V = \frac{E}{q}[/tex]

E is 20MeV, q is 2e
 
Last edited:
  • #4


Originally posted by ShawnD
Just start multiplying stuff until the units work out the way you want them to.
That always seems to work.
 
  • #5
Thanks guys.

You guys are the best.
 

1. What is an alpha particle?

An alpha particle is a type of ionizing radiation that consists of two protons and two neutrons. It is commonly emitted by radioactive materials.

2. How does alpha particle flow relate to current?

Alpha particle flow refers to the movement of alpha particles through a material. When these particles pass through a material, they can cause collisions with the atoms and create a flow of electric charge, which is known as current.

3. What is resistance in relation to alpha particle flow?

Resistance is the measure of how difficult it is for current to flow through a material. In the context of alpha particle flow, resistance refers to how easily alpha particles can move through a material. Materials with high resistance will impede the flow of alpha particles and thus decrease current.

4. How is current affected by the number of alpha particles?

The number of alpha particles has a direct impact on the amount of current that can flow through a material. More alpha particles will result in a higher current, while fewer alpha particles will result in a lower current.

5. What is the relationship between alpha particle flow and electrical conductivity?

Electrical conductivity is a measure of how easily a material allows electric charge to flow through it. In the case of alpha particle flow, materials with high electrical conductivity will allow alpha particles to move more freely and thus have a higher current, while materials with low electrical conductivity will impede alpha particle flow and have a lower current.

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