String Trimmer Batteries - same weight charged and empty

[steve_bank]

There are several mechanisms for generating photons. Don;t forget the wave particle duality.

Thermal photons as in BB radiation.

AC electric current in a conductor giving rise rt EM radiation. Antennas.
t
Solid state photo emitters like light emitting diodes and laser diodes.

In all cases there is an energy balaqnce, but it may not seem obvious unless you are familiar with the model and units. The form of the balance changes but energy must alwats add up. No exceptions.

Consider a light emitting diode. To understand the mechanism at the quantum scale you have to first understand electrons, atomic states and bangaps, and photons expressed in electron volts, eV Ev can be converted to joules. The wavelenth of a photon is an expression of photon energy. When a photon is emitted from an LED the energy or wavelength of the photon equals the atomic bandgap voltage in eV. Energy in ev must allays add up going back to the source power supply.

The quantum efficiency of an LED is expressed inphotons per electrons.

You can look up the LED equations for current to photons and the energy transfers.

When a photon at the bandgap voltage of a photodetector an atom adsorbs the photon with an increase in energy of the photon in eV. The quantum efficiency of a detector is electrons per photon.

LOT always applies to energy conversion. In this case energy added to electrons by the power supply to energy added by electrons to an atom to the energy of an emoted photon. Enemy along the chain must add up including heat resulting from inefficiency.

If you believe the current iout of an incandescent bulb will always be lower than what goes in then conservation still applies.



An example is worth 1000 net references.

connect a batty to a bulb with wires. Draw a bubble or thermodynamic boundary around the bulb. Energy in to the bulb or system is current from the battery. Energy out of the system is photons and return current to the battery. It must all add up.

LOT applies to energy and mass crossing a system boundary.

 

[Bronzeage]

There are several mechanisms for generating photons. Don;t forget the wave particle duality.

Thermal photons as in BB radiation.

AC electric current in a conductor giving rise rt EM radiation. Antennas.
t
Solid state photo emitters like light emitting diodes and laser diodes.

In all cases there is an energy balaqnce, but it may not seem obvious unless you are familiar with the model and units. The form of the balance changes but energy must alwats add up. No exceptions.

Consider a light emitting diode. To understand the mechanism at the quantum scale you have to first understand electrons, atomic states and bangaps, and photons expressed in electron volts, eV Ev can be converted to joules. The wavelenth of a photon is an expression of photon energy. When a photon is emitted from an LED the energy or wavelength of the photon equals the atomic bandgap voltage in eV. Energy in ev must allays add up going back to the source power supply.

The quantum efficiency of an LED is expressed inphotons per electrons.

You can look up the LED equations for current to photons and the energy transfers.

When a photon at the bandgap voltage of a photodetector an atom adsorbs the photon with an increase in energy of the photon in eV. The quantum efficiency of a detector is electrons per photon.

LOT always applies to energy conversion. In this case energy added to electrons by the power supply to energy added by electrons to an atom to the energy of an emoted photon. Enemy along the chain must add up including heat resulting from inefficiency.

If you believe the current iout of an incandescent bulb will always be lower than what goes in then conservation still applies.



An example is worth 1000 net references.

connect a batty to a bulb with wires. Draw a bubble or thermodynamic boundary around the bulb. Energy in to the bulb or system is current from the battery. Energy out of the system is photons and return current to the battery. It must all add up.

LOT applies to energy and mass crossing a system boundary.

So, you're saying my flashlight with the dead battery weighs less than the one with the good battery?

 

[steve_bank]

There are several mechanisms for generating photons. Don;t forget the wave particle duality.

Thermal photons as in BB radiation.

AC electric current in a conductor giving rise rt EM radiation. Antennas.
t
Solid state photo emitters like light emitting diodes and laser diodes.

In all cases there is an energy balaqnce, but it may not seem obvious unless you are familiar with the model and units. The form of the balance changes but energy must alwats add up. No exceptions.

Consider a light emitting diode. To understand the mechanism at the quantum scale you have to first understand electrons, atomic states and bangaps, and photons expressed in electron volts, eV Ev can be converted to joules. The wavelenth of a photon is an expression of photon energy. When a photon is emitted from an LED the energy or wavelength of the photon equals the atomic bandgap voltage in eV. Energy in ev must allays add up going back to the source power supply.

The quantum efficiency of an LED is expressed inphotons per electrons.

You can look up the LED equations for current to photons and the energy transfers.

When a photon at the bandgap voltage of a photodetector an atom adsorbs the photon with an increase in energy of the photon in eV. The quantum efficiency of a detector is electrons per photon.

LOT always applies to energy conversion. In this case energy added to electrons by the power supply to energy added by electrons to an atom to the energy of an emoted photon. Enemy along the chain must add up including heat resulting from inefficiency.

If you believe the current iout of an incandescent bulb will always be lower than what goes in then conservation still applies.



An example is worth 1000 net references.

connect a batty to a bulb with wires. Draw a bubble or thermodynamic boundary around the bulb. Energy in to the bulb or system is current from the battery. Energy out of the system is photons and return current to the battery. It must all add up.

LOT applies to energy and mass crossing a system boundary.

So, you're saying my flashlight with the dead battery weighs less than the one with the good battery?

What I am saying is I read books and applied thermodynamics. I believe there is no weight loss. In the case of an incandescent bulb the energy to create photons comes from current cresting temperature through the resistance of the bulb.

In the case of an LED I'd have to look the mechanisms involving electrons-holes pairs to be sure , which I am not interested in doing. Haven't looked at it in a long time.



If you search the net I'd bet it has been discussed.

 

[Wiploc]

So, you're saying my flashlight with the dead battery weighs less than the one with the good battery?

I'll say that, yes.

[TD="align: right"]1.00784[/TD]
[TD="colspan: 3"] Atomic weight of hydrogen[/TD]
[TD="width: 64"][/TD]
[TD="width: 64"][/TD]

[TD="align: right"]1.00784[/TD]
[TD="colspan: 3"] Atomic weight of hydrogen[/TD]

[TD="align: right"]15.999[/TD]
[TD="colspan: 3"] Atomic weight of oxygen[/TD]

[TD="align: right"]18.01468[/TD]
[TD="colspan: 3"] Atomic weight of 2 H and 1 O.[/TD]

[TD="align: right"]18.01528[/TD]
[TD="colspan: 3"] Atomic weight of water[/TD]

[TD="align: right"]0.0006[/TD]
[TD="colspan: 5"] How much more water weighs than 2 H and 1 O.[/TD]

The difference (.0006) is (multiplied by the number of oxygen atoms in your hydrogen/oxygen battery) the difference in weight between your charged and discharged battery.

That same number (.0006 times the number of oxygen atoms involved) multiplied by c squared is the amount of energy (at an impossible 100% efficiency) that you get out of your battery and/or the energy required to recharge it.

It was big news when somebody figured out that, for instance, sodium chloride (NaCl) doesn't weigh the same as sodium (Na) plus chlorine (Cl).

 

[bilby]

There are several mechanisms for generating photons. Don;t forget the wave particle duality.

Thermal photons as in BB radiation.

AC electric current in a conductor giving rise rt EM radiation. Antennas.
t
Solid state photo emitters like light emitting diodes and laser diodes.

In all cases there is an energy balaqnce, but it may not seem obvious unless you are familiar with the model and units. The form of the balance changes but energy must alwats add up. No exceptions.

Consider a light emitting diode. To understand the mechanism at the quantum scale you have to first understand electrons, atomic states and bangaps, and photons expressed in electron volts, eV Ev can be converted to joules. The wavelenth of a photon is an expression of photon energy. When a photon is emitted from an LED the energy or wavelength of the photon equals the atomic bandgap voltage in eV. Energy in ev must allays add up going back to the source power supply.

The quantum efficiency of an LED is expressed inphotons per electrons.

You can look up the LED equations for current to photons and the energy transfers.

When a photon at the bandgap voltage of a photodetector an atom adsorbs the photon with an increase in energy of the photon in eV. The quantum efficiency of a detector is electrons per photon.

LOT always applies to energy conversion. In this case energy added to electrons by the power supply to energy added by electrons to an atom to the energy of an emoted photon. Enemy along the chain must add up including heat resulting from inefficiency.

If you believe the current iout of an incandescent bulb will always be lower than what goes in then conservation still applies.



An example is worth 1000 net references.

connect a batty to a bulb with wires. Draw a bubble or thermodynamic boundary around the bulb. Energy in to the bulb or system is current from the battery. Energy out of the system is photons and return current to the battery. It must all add up.

LOT applies to energy and mass crossing a system boundary.

So, you're saying my flashlight with the dead battery weighs less than the one with the good battery?

What I am saying is I read books

Apparently not very carefully; Or not the right books.

and applied thermodynamics.

Incorrectly.

I believe there is no weight loss.

Reality doesn't give a shit what you believe.

In the case of an incandescent bulb the energy to create photons comes from current cresting temperature through the resistance of the bulb.

True, but completely irrelevant.

In the case of an LED I'd have to look the mechanisms involving electrons-holes pairs to be sure , which I am not interested in doing. Haven't looked at it in a long time.

As it's not even slightly relevant, I suggest you don't bother.

If you search the net I'd bet it has been discussed.

Doubtless. And by lots of idiots and ignoramuses.

The fact remains that energy and mass are equivalent; And that a battery in a power tool or flashlight is not a closed system.

 

[barbos]

So, you're saying my flashlight with the dead battery weighs less than the one with the good battery?

I'll say that, yes.

[TD="align: right"]1.00784[/TD]
[TD="colspan: 3"] Atomic weight of hydrogen[/TD]
[TD="width: 64"][/TD]
[TD="width: 64"][/TD]

[TD="align: right"]1.00784[/TD]
[TD="colspan: 3"] Atomic weight of hydrogen[/TD]

[TD="align: right"]15.999[/TD]
[TD="colspan: 3"] Atomic weight of oxygen[/TD]

[TD="align: right"]18.01468[/TD]
[TD="colspan: 3"] Atomic weight of 2 H and 1 O.[/TD]

[TD="align: right"]18.01528[/TD]
[TD="colspan: 3"] Atomic weight of water[/TD]

[TD="align: right"]0.0006[/TD]
[TD="colspan: 5"] How much more water weighs than 2 H and 1 O.[/TD]

The difference (.0006) is (multiplied by the number of oxygen atoms in your hydrogen/oxygen battery) the difference in weight between your charged and discharged battery.

Actually, this is all incorrect because H2O should be lighter than H+H+O. What happened is that you were not careful with isotopes

 

[Loren Pechtel]

What I am saying is I read books and applied thermodynamics. I believe there is no weight loss. In the case of an incandescent bulb the energy to create photons comes from current cresting temperature through the resistance of the bulb.

In the case of an LED I'd have to look the mechanisms involving electrons-holes pairs to be sure , which I am not interested in doing. Haven't looked at it in a long time.



If you search the net I'd bet it has been discussed.

E = mc^². The charged battery contains chemicals with higher energy levels.

 

[steve_bank]

What I am saying is I read books and applied thermodynamics. I believe there is no weight loss. In the case of an incandescent bulb the energy to create photons comes from current cresting temperature through the resistance of the bulb.

In the case of an LED I'd have to look the mechanisms involving electrons-holes pairs to be sure , which I am not interested in doing. Haven't looked at it in a long time.



If you search the net I'd bet it has been discussed.

E = mc^². The charged battery contains chemicals with higher energy levels.

I don't see where E=mc^2 has anything to do with a battery's potential difference between terminal At least computationally. It never appears in any of my texts on solid state theory. For photo emitters like an LED the theory is in terms of electron, photon, and atomic bandgap energy expressed in eV. Quantum theory.

For an incandescent build it is BB radiation powered by thermal energy. Take a bar of metal and heat it enough with a flame and it will glow in the visible spectrum. In a bulb heat is supplied by reliance heating of the filament.

E=mc^2 is the energy stored in the atomic forces. What gets released in fission by splitting an atom.

A battery creats a volatge potenial that creates a staic electric field acoss a conductor that exerts force on electron.

In an unconnected wire thermal electrons are randomly bouncing around. At a cross section the number of electrons crossing in one direction equal electrons going the other way. This is called charge neutrality. There is no net current in any direction.

Put a battery across the wire and the electric field across the wire creates a net drift in one direction. An electron from the battery does not enter one end of the wire, travel down the wire, and pop out the other end back to the battery. There are conduction animations online.

A good analogy for a battery or any voltage source is a water pump. The water analogy for current is common. You can replce the battery with a generator or transformer and the problem does not change.

Like I said it is a good question, it brings in a lot.

 

[barbos]

Take an ideal gas "battery" and calculate it's weight using STO and you will find out that its mass will depend on temperature and hence internal energy with full accordance with E=mc^2

E=mc^2 is built-in into STO.

 

[skepticalbip]

What I am saying is I read books and applied thermodynamics. I believe there is no weight loss. In the case of an incandescent bulb the energy to create photons comes from current cresting temperature through the resistance of the bulb.

In the case of an LED I'd have to look the mechanisms involving electrons-holes pairs to be sure , which I am not interested in doing. Haven't looked at it in a long time.



If you search the net I'd bet it has been discussed.

E = mc^². The charged battery contains chemicals with higher energy levels.

I don't see where E=mc^2 has anything to do with a battery's potential difference between terminal At least computationally. It never appears in any of my texts on solid state theory.
... snip ...
.

It doesn't appear in your texts because the mass contributed by the energy difference between a dead battery and a fully charged battery is insignificant (much less than measurement error) for normal concerns. You will also find in texts that if two cars are approaching each other from opposite directions, each traveling a 50MPH, then each will measure the closing speed to be 100MPH. This also is incorrect because of time dilation and Lorentz contraction but the difference from the 100MPH will be so small as to be insignificant.

The differences between Newtonian physics and Einstein only becomes significant for extremely high relative velocities, extremely great masses, and extremely high energy differences... but the differences are still there in our human scale existence, just not sufficiently noticeable to be of any importance. For human scale events, you would have to go out quite a few decimal places in your calculations to see the difference.

 

[barbos]

I don't see where E=mc^2 has anything to do with a battery's potential difference between terminal At least computationally. It never appears in any of my texts on solid state theory.
... snip ...
.

It doesn't appear in your texts because the mass contributed by the energy difference between a dead battery and a fully charged battery is insignificant (much less than measurement error) for normal concerns.

Yes, there is more than 9 orders of magnitude between typical chemical energy and energy due to mass.
I mean typical potential is in the order of 1 volt and mass of the hydrogen atom is 10^9 electronvolt.

 

[Wiploc]

So, you're saying my flashlight with the dead battery weighs less than the one with the good battery?

I'll say that, yes.

[TD="align: right"]1.00784[/TD]
[TD="colspan: 3"] Atomic weight of hydrogen[/TD]

[TD="width: 64"][/TD]

[TD="align: right"]1.00784[/TD]
[TD="colspan: 3"] Atomic weight of hydrogen[/TD]

[TD="align: right"]15.999[/TD]
[TD="colspan: 3"] Atomic weight of oxygen[/TD]

[TD="align: right"]18.01468[/TD]
[TD="colspan: 3"] Atomic weight of 2 H and 1 O.[/TD]

[TD="align: right"]18.01528[/TD]
[TD="colspan: 3"] Atomic weight of water[/TD]

[TD="align: right"]0.0006[/TD]
[TD="colspan: 5"] How much more water weighs than 2 H and 1 O.[/TD]

The difference (.0006) is (multiplied by the number of oxygen atoms in your hydrogen/oxygen battery) the difference in weight between your charged and discharged battery.

Actually, this is all incorrect because H2O should be lighter than H+H+O. What happened is that you were not careful with isotopes

I just asked google for atomic weights.

But you're right that H20 should be lighter than H+H+O. Burning hydrogen to get water is exothermic. To go the other way, we'd have to put energy back in.

 

[fromderinside]

Yeah that Chinese endo exo thing written by Yin Yan I think.

 

[Loren Pechtel]

E = mc^². The charged battery contains chemicals with higher energy levels.

I don't see where E=mc^2 has anything to do with a battery's potential difference between terminal At least computationally. It never appears in any of my texts on solid state theory. For photo emitters like an LED the theory is in terms of electron, photon, and atomic bandgap energy expressed in eV. Quantum theory.

It wouldn't--the amount of mass involved would be too small to measure.

E=mc^2 is the energy stored in the atomic forces. What gets released in fission by splitting an atom.

E=mc^² applies to all forces, not just atomic ones. It's just that chemical energy doesn't translate into enough mass to be meaningful.

 

[steve_bank]

I don't see where E=mc^2 has anything to do with a battery's potential difference between terminal At least computationally. It never appears in any of my texts on solid state theory.
... snip ...
.

It doesn't appear in your texts because the mass contributed by the energy difference between a dead battery and a fully charged battery is insignificant (much less than measurement error) for normal concerns. You will also find in texts that if two cars are approaching each other from opposite directions, each traveling a 50MPH, then each will measure the closing speed to be 100MPH. This also is incorrect because of time dilation and Lorentz contraction but the difference from the 100MPH will be so small as to be insignificant.

The differences between Newtonian physics and Einstein only becomes significant for extremely high relative velocities, extremely great masses, and extremely high energy differences... but the differences are still there in our human scale existence, just not sufficiently noticeable to be of any importance. For human scale events, you would have to go out quite a few decimal places in your calculations to see the difference.

If I really had to get into I would first look at the mass and energy balance chemical equations in the battery during discharge.. For a regular light bulb the bulb is a simple resistance. The battery and the resistor form a circuit in which current is the same at any point in the circuit. If you want to argue that go ahead. It is textbook theory. We are talking quantum not relativistic.

The question asked was is the electrons going back to the battery less than the electrons leaving the battery. I say the6y are the same in the case of a light bulb. If I replace the bulb with a simple resistor nothing changes.

We can drill down into how heat causes thermal BB radiation. The bulb is always radiating photons even wen it is off. Any object above 0K radiates. At a certain temperature the spectrum is visible. Atoms in a sense are in monition about their positions in a sold. Adding neat changes bandgaps. It is why transistors change characteristics with temperature. At some point energy is released as photons. The wavelength of the photons equates to the bandgap voltages which change with temperature. Everything atomic changes with temperature.

mc^2 is not a factor. That energy is accessible in nuclear reactions. Not in ordinary chemical reactions.

 

[Loren Pechtel]

I don't see where E=mc^2 has anything to do with a battery's potential difference between terminal At least computationally. It never appears in any of my texts on solid state theory.
... snip ...
.

It doesn't appear in your texts because the mass contributed by the energy difference between a dead battery and a fully charged battery is insignificant (much less than measurement error) for normal concerns.

Yes, there is more than 9 orders of magnitude between typical chemical energy and energy due to mass.
I mean typical potential is in the order of 1 volt and mass of the hydrogen atom is 10^9 electronvolt.

Thank you--that provides a convenient measure of showing the scale.

 

[bilby]

I don't see where E=mc^2 has anything to do with a battery's potential difference between terminal At least computationally. It never appears in any of my texts on solid state theory.
... snip ...
.

It doesn't appear in your texts because the mass contributed by the energy difference between a dead battery and a fully charged battery is insignificant (much less than measurement error) for normal concerns. You will also find in texts that if two cars are approaching each other from opposite directions, each traveling a 50MPH, then each will measure the closing speed to be 100MPH. This also is incorrect because of time dilation and Lorentz contraction but the difference from the 100MPH will be so small as to be insignificant.

The differences between Newtonian physics and Einstein only becomes significant for extremely high relative velocities, extremely great masses, and extremely high energy differences... but the differences are still there in our human scale existence, just not sufficiently noticeable to be of any importance. For human scale events, you would have to go out quite a few decimal places in your calculations to see the difference.

If I really had to get into I would first look at the mass and energy balance chemical equations in the battery during discharge.. For a regular light bulb the bulb is a simple resistance. The battery and the resistor form a circuit in which current is the same at any point in the circuit. If you want to argue that go ahead. It is textbook theory. We are talking quantum not relativistic.

The question asked was is the electrons going back to the battery less than the electrons leaving the battery. I say the6y are the same in the case of a light bulb. If I replace the bulb with a simple resistor nothing changes.

We can drill down into how heat causes thermal BB radiation. The bulb is always radiating photons even wen it is off. Any object above 0K radiates. At a certain temperature the spectrum is visible. Atoms in a sense are in monition about their positions in a sold. Adding neat changes bandgaps. It is why transistors change characteristics with temperature. At some point energy is released as photons. The wavelength of the photons equates to the bandgap voltages which change with temperature. Everything atomic changes with temperature.

mc^2 is not a factor. That energy is accessible in nuclear reactions. Not in ordinary chemical reactions.

You are wrong. And you are embarrassing yourself by repeating your error, even though it has been very patiently pointed out to you by posters with a lot more patience than I.

Energy is energy. It's always equal to mc². It matters not a whit whether it's chemical or nuclear or anything else.

The mass due to chemical energy is minuscule, and is usually disregarded. But it's real and measurable (albeit with very sensitive equipment).

Your tendency to respond to having your errors pointed out by retreating into walls of irrelevancies, while doubling down on your mistakes, makes me terrified to think you might have been involved in the design of aircraft on which I, or people I care for, might fly.

Your approximations do not trump the fundamentals. Mass/Energy equivalence is universal - unlike LoT, which apply only to closed systems (of which a battery powered electrical circuit is not one).

 

[skepticalbip]

I don't see where E=mc^2 has anything to do with a battery's potential difference between terminal At least computationally. It never appears in any of my texts on solid state theory.
... snip ...
.

It doesn't appear in your texts because the mass contributed by the energy difference between a dead battery and a fully charged battery is insignificant (much less than measurement error) for normal concerns. You will also find in texts that if two cars are approaching each other from opposite directions, each traveling a 50MPH, then each will measure the closing speed to be 100MPH. This also is incorrect because of time dilation and Lorentz contraction but the difference from the 100MPH will be so small as to be insignificant.

The differences between Newtonian physics and Einstein only becomes significant for extremely high relative velocities, extremely great masses, and extremely high energy differences... but the differences are still there in our human scale existence, just not sufficiently noticeable to be of any importance. For human scale events, you would have to go out quite a few decimal places in your calculations to see the difference.

If I really had to get into I would first look at the mass and energy balance chemical equations in the battery during discharge.. For a regular light bulb the bulb is a simple resistance. The battery and the resistor form a circuit in which current is the same at any point in the circuit. If you want to argue that go ahead. It is textbook theory. We are talking quantum not relativistic.

.... snip ....
.

It has nothing to do with quantum mechanics. It is about the reality of physics. You, however, are correct in that it is all about "mass and energy balance". Mass is a special case of energy. When you balance your equation, the mass/energy of the battery is the question. A charged battery has more mass/energy than a dead battery.

As you use the battery the energy level is reduced but that energy does not vanish, it is converted to heat, light, kinetic energy, etc. and removed from the battery depending on what the battery is being used to power. Charging the battery then increases the mass/energy again.

As I see, you are denying that there is a equivalence between mass and energy. Finding that there was an equivalence was a major breakthrough around the end of the 19th century. You need to get a bit more advanced physics text. The one you are relying on is great for every day human scale calculations because we generally don't really care about being precise out to ten or twenty decimal places in our every day life.

 

[barbos]

mc^2 is not a factor. That energy is accessible in nuclear reactions. Not in ordinary chemical reactions.

It applies to both cases equally, E=mc² is fundamental.

 

[skepticalbip]

mc^2 is not a factor. That energy is accessible in nuclear reactions. Not in ordinary chemical reactions.

It applies to both cases equally, E=mc² is fundamental.

It looks, to me, like he was denying that m=E/c² for any energy too.