Measuring Intensity of Sources of Light

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To measure the intensities of different light sources like candlelight and tungsten filament, a setup is needed that includes a narrow tube to direct light to a sensor. The sensor converts light into electricity, allowing for quantifiable measurements. Key metrics to consider include intensity (W/sr), irradiance (W/m² at the observer), and radiant emittance (W/m² at the source). It's important to clarify which measurement is desired, with a suggestion that irradiance may be the focus. The terminology used in defining these concepts should be precise to avoid confusion, particularly distinguishing between radiant intensity and general intensity.
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how do i measure the intensities of different sources of light?
eg. candle light, tungsten filament etc.
 
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You must have at least two things : first, something that can direct light from the source to the cell and secondly the cell (sensor) that can convert light into electricity.
The 1st part can be made very simply as a narrow tube which is long enough so the sensor can only receive light from the source.
 
Be careful with your quantities here.

Intensity = W/sr
Irradiance = W/m^2 (at the observer)
Radiant Emittance = W/m^2 (at the source)

Which specifically do you want to measure (I'm guessing Irradiance).

Claude.
 
Claude, that's an unusual set of definitions, you should consider calling W/sr "radiant intensity" to distinguish it from the notion of "intensity" that is normally used in at least early undergraduate physics.
 
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