Joules, Power Over Distance

[Spyderz20x6]

I was sitting around, bored (as usual), and i remembered the Joule. The Joule is truly an interesting unit, because it is power over distance. So, if one were to convert milliwats and see how much Joules is equal to 1 milliwatt, we could measure the power of a laser using distance in meters (a joule is the amount of energy it takes to lift a object that weighs one newton one meter). Is it actually possible to measure laser power using Joules? I got confused in my research over all the different mesaurments :

 

[Switch]

No it is not.Power is measured in Watts, energy is measured in Joules.We measure laser pulses in Joules.But you see, energy and power are not the same thing like you make it sound like.1J is a measure for energy, 1W is a measure for power.1W=1J/s => Power=energy/time => energy=power*time.

 

[Spyderz20x6]

No it is not.Power is measured in Watts, energy is measured in Joules.We measure laser pulses in Joules.But you see, energy and power are not the same thing like you make it sound like.1J is a measure for energy, 1W is a measure for power.1W=1J/s => Power=energy/time => energy=power*time.

Yes, i know. That was my question (although i didn't make it very clear). My question was, is it possible to measure laser power in distance using a completely different unit (Joules is energy, watts is power)? It's almost the same thing as saying, could you measure volts using watts? What kind of measurement would you use to measure how much laser power decreases at a certain distance?

 

[Maelstrom]

Cant measure volts in watts, Volts is electrical potential...
Anyway, for your last questoin, I would say no. There are so many things that affect the power or the distance. I assume the only reasons the power decreases with distance is 1) light might be less focused and 2) airborne particles block its path. A laser beam in a vacuum would probally have the same power( assuming it is focused to each spot) if it was 1 mm away or 20m away.

 

[Spyderz20x6]

Cant measure volts in watts, Volts is electrical potential...
Anyway, for your last questoin, I would say no. There are so many things that affect the power or the distance. I assume the only reasons the power decreases with distance is 1) light might be less focused and 2) airborne particles block its path. A laser beam in a vacuum would probally have the same power( assuming it is focused to each spot) if it was 1 mm away or 20m away.

I know you can't measure volts in watts, thats what my point was. Watts is power, volts is electricity.

For your other answer, thanks for all the info, i never really thought of airbore particles...

 

[pseudonomen137]

question was, is it possible to measure laser power in distance using a completely different unit (Joules is energy, watts is power)? It's almost the same thing as saying, could you measure volts using watts?

You're right, its the same as trying to measure volts by watts, they're both impossibilities!

Theoretically, why would a laser natively lose power over distance? If there's nothing to block it, why would any power be lost at all? That would violate conservation of energy. However, things do diffuse a block it in normal conditions - air for instance. How much that will dissipate power over distance is dependant on a deluge of variables including humidity and other particulates in the atmosphere.

 

[Maelstrom]

[quote author=Maelstrom link=1212963525/0#3 date=1212967562]Cant measure volts in watts, Volts is electrical potential...
Anyway, for your last questoin, I would say no. There are so many things that affect the power or the distance. I assume the only reasons the power decreases with distance is 1) light might be less focused and 2) airborne particles block its path. A laser beam in a vacuum would probally have the same power( assuming it is focused to each spot) if it was 1 mm away or 20m away.

I know you can't measure volts in watts, thats what my point was. Watts is power, volts is electricity.

For your other answer, thanks for all the info, i never really thought of airbore particles...[/quote]
Sorry, I was kinda scanning over it real quick

 

[NovoRei]

Joule, watt, work, all are energy.

 

[pseudonomen137]

Joule, watt, work, all are energy.

Apples and Oranges - all are fruit.

 

[pullbangdead]

[quote author=NovoRei link=1212963525/0#7 date=1212971763]Joule, watt, work, all are energy.

Apples and Oranges - all are fruit.[/quote]

Quote of the day.

 

[Petrovski]

Switch is right. Power = energy/time. 1W=1J/second.

But sure it's possible to use different units for power: BTU, calorie, horsepower, etc.

 

[Switch]

Switch is right. Power = energy/time. 1W=1J/second.

But sure it's possible to use different units for power: BTU, calorie, horsepower, etc.

Isn't the Calorie a unit for energy? :

Anyway, the thing is , it's just absurd.It's like tring to measure distance in mph or k/h.
Behold:

How many mph are there from your house to school

...how senseless it is.

So if you want to measure a laser's output in Joules , you just have to add time into the equation.For instance a 200mW laser outputs 200mJ/s (thats two hundred miliJoules every second) so you hold it on for five seconds and it has outputed a total of 1J.

 

[Petrovski]

Isn't the Calorie a unit for energy? :

Uhm yeah it is.  :-[ Scrap that one.

Anyway, the thing is , it's just absurd.It's like tring to measure distance in mph or k/h.
Behold:

How many mph are there from your house to school

...how senseless it is.

So if you want to measure a laser's output in Joules , you just have to add time into the equation.For instance a 200mW laser outputs 200mJ/s (thats two hundred miliJoules every second) so you hold it on for five seconds and it has outputed a total of 1J.

Yup. Not sure why anybody would want to use that type of unit. I'd say one should use the unit that is most common or makes most sense. Nobody would measure the output of a laser in horsepower for example.

 

[f22warzone]

hey i thing a 400 horsepower laser would be cool..... it almost sounds like somting WL would sell

edit*
now that i think about it wasnt their an thread about sombody on ebay selling a 35 horsepower laser?
*edit