How does electron speed affect electric power?

[Aakash Sunkari]

TL;DR

I have a beta emitter which produces electrons with around 1 MeV of kinetic energy, on average. If I were to use these electrons for electricity, how does the kinetic energy of the electron affect the electrical energy created by the movement of these electrons?

I've got a quick question on the relationship between the kinetic energy of individual electrons and the total electrical energy they create.

I have a radioisotope - a beta emitter - which produces electrons with around 1 MeV (1.60218×10^-13 Joules / 4.45049×10^-17 Watt-hours) of energy.

I keep researching the notion of electrical energy online, and I find that it is the result of either a.) electric potential or b.) kinetic energy. Furthermore, I also note that Electric Energy is related to two factors: the voltage and the current.

Given that 1 eV is equal to the amount of kinetic energy an electron gains when moved across a potential difference of one volt, am I correct to assume that since I am producing electrons with 4.45049×10^-17 Watt-hours of kinetic energy, I will be able to obtain 4.45049×10^-17 Watt-hours of electrical energy, assuming that this is a perfect system and no energy is lost due to heat?

Please correct me if any part of my understanding is wrong.

Thank you all in advance!

 

[anuttarasammyak]

How can we generate electric power with electrons that have 1 MeV kinetic energy ? A blunt idea with low efficiency comes to my mind. Heat a target by bombard of the electrons and make it a heat source for electricity generation as fire and nuclear power plants.

EDIT: For power generation from heat source, thermoelectric conversion element is useful as it is in nuclear batteries.

 

[Aakash Sunkari]

How can we generate electric power by electrons that have kinetic energy is 1 MeV ? A blunt idea of low efficiency comes to my mind. Heat a target by bombard of the electrons and make it a heat source for electricity generation as fire and nuclear power plants.

I wasn't thinking necessarily using the electrons for heat generation, but perhaps using the flow of the electrons as a "current" - since these electrons are already charged particles. So would this electric energy be equivalent to the kinetic energy these electrons possess?

 

[hutchphd]

Electrons moving in a wire mostly contain electrical potential (volts) energy. This is relatively easy to manipulate. A 1 MeV beta particle has already converted any potential into Kinetic Energy. The cat is out of the bag. Measuring its energy in electron volts makes it no easier to use it as a current source for electric power.

 

[anuttarasammyak]

but perhaps using the flow of the electrons as a "current"

Magnetohydrodynamic generator could be of your interest.

 

[anorlunda]

You're missing key concepts here on electrical conduction. Read these articles first, then come back here.

https://en.wikipedia.org/wiki/Drude_model
https://en.wikipedia.org/wiki/Drift_velocity

p.s. I changed the title to say power instead of energy because that sounds like what you're asking about.

 

[Tom.G]

Here is an article that covers that possibility.
https://arxiv.org/ftp/arxiv/papers/1511/1511.07427.pdf

Above found with:
https://www.google.com/search?&q=atomic+battery+seminar+pdf+download

Also try the search with just: atomic battery

Many years ago I got a contract to investigate small power sources with over 100 years of lifetime. Yes, the approach you are asking about was evaluated and came in at the absolute bottom of the list for terrestial use. There are just too many other power sources available. You can get a very high voltage from an atomic battery but the power density is really tiny.

Cheers,
Tom

p.s. The client eventually settled on a wind-up spring that a user could wind/rewind as needed. Their logic was if there was no one to wind it there was no sense in storing the energy.
Flawless!

 

[Rive]

If you are talking about energy, then the 'eV' is not really an unit of measure in the right dimension. It is eV/piece. To get the energy right, first you need to get the amount of electrons right.

The amount of electrons in a given time is actually called 'current', what will depend on the amount of decays in your beta emitter over a given time.

 

[gleem]

Given that 1 eV is equal to the amount of kinetic energy an electron gains when moved across a potential difference of one volt, am I correct to assume that since I am producing electrons with 4.45049×10-17 Watt-hours of kinetic energy, I will be able to obtain 4.45049×10-17 Watt-hours of electrical energy, assuming that this is a perfect system and no energy is lost due to heat?

All the energy will be lost as heat. There is no change in net charge within the material.

 

[DaveE]

Since you specified "a perfect system and no energy is lost due to heat", then yes, I'm sure it could be done. For example decelerate the electron in an e-field and when it stops it will have only electric potential energy equal to the original kinetic energy.

Of course, as everyone has said, it's not very practical compared to other solutions.

 

[rbelli1]

p.s. The client eventually settled on a wind-up spring that a user could wind/rewind as needed. Their logic was if there was no one to wind it there was no sense in storing the energy.
Flawless!

That's a perfect example of why you need to understand the intent of the question not just the actual question asked. The intent may sometimes only be loosely related to series of words making up the question. Sometimes not at all.

BoB

 

[dlgoff]

From the thread's title "How does electron speed affect electric power?" makes me want to post this from http://hyperphysics.phy-astr.gsu.edu/hbase/electric/miccur.html

Although your light turns on very quickly when you flip the switch, and you find it impossible to flip off the light and get in bed before the room goes dark, the actual drift velocity of electrons through copper wires is very slow. It is the change or "signal" which propagates along wires at essentially the speed of light.