Difference between intensity and power

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Discussion Overview

The discussion centers around the distinction between power and intensity, exploring definitions and relationships between these two concepts in the context of physics, particularly as they relate to laser specifications and energy flow.

Discussion Character

  • Conceptual clarification, Technical explanation

Main Points Raised

  • One participant questions whether power is defined over a specific beam spot size while intensity varies with time.
  • Another participant states that power is defined as energy per time, while intensity is described as power per area.
  • A subsequent post reiterates the definition of intensity as power per area.
  • Further clarification is provided that intensity is measured in watts per square meter, with an example of sunlight intensity given as 1400 W/m².

Areas of Agreement / Disagreement

Participants generally agree on the definitions of power and intensity, but there is some uncertainty regarding the relationship between intensity and time as mentioned in the initial post.

Contextual Notes

The discussion does not resolve the initial participant's impression about intensity varying with time, leaving that aspect open to interpretation.

watertreader
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Is there a difference between power and intensity?

From some of the literature read(from laser specification), the impression given to me is that power is defined rather as determined over a particular beam spot size(area quantity) while intensity is defined as a quantity that is varied with time?

Is that true?
 
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Typically: Power is energy per time; Intensity is power per area.
 
Intensity is power per area ?
 
Yes: watts per square meter, or joules per second per square meter, measured on a surface oriented perpendicular to the direction of energy flow. Example: the typical intensity of sunlight is 1400 W/m^2.
 

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