I have a light bulb and i'm trying to figure out what the intensity of it is. This is because I have a solar cell and i'm trying to measure the efficiency of it. I know the power out from the solar cell and now all i need to know the power into the solar cell. I have a lightbulb that's spherical. It says that its 320 lumens, uses 40 watts. It's also a soft incendescent lightbulb. From this infomration am I able to determine the amount of energy the light emitted has?
How do i determine the intensity of my light source from this information?
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Moonshadow
Enlightened
Lumens per watt into your favourite search engine will send you here . . .
http://en.wikipedia.org/wiki/Luminous_efficacy
Essentially, around 683 Lumens per Watt is the maximum efficiency you could possibly hope to achive (i.e. when 100% of the electrical energy is converted into green photons), so your light is turning at most around 0.5 Watts into visible photons (depends a bit on the wavelengths involved) - so perhaps a little bit over 1% efficient.
This is different from the efficiency of your solar cell though - that would depend on the ratio of electrical energy out to energy in from the sunlight falling on the cell.
What's your setup ? Are you using the solar cell to power the light or shining the output from the bulb onto the cell ?
http://en.wikipedia.org/wiki/Luminous_efficacy
Essentially, around 683 Lumens per Watt is the maximum efficiency you could possibly hope to achive (i.e. when 100% of the electrical energy is converted into green photons), so your light is turning at most around 0.5 Watts into visible photons (depends a bit on the wavelengths involved) - so perhaps a little bit over 1% efficient.
This is different from the efficiency of your solar cell though - that would depend on the ratio of electrical energy out to energy in from the sunlight falling on the cell.
What's your setup ? Are you using the solar cell to power the light or shining the output from the bulb onto the cell ?
Last edited:
Marduke
Flashaholic
Any estimate you could make would be larger than the possible spread in solar panel efficiency.
The short answer is no, you really don't have the equipment to calculate it based off the power output from a light bulb. You would have a much more accurate answer of simply looking up the specs for the type of solar panel you own, and how old it is (some types degrade over time). You might also be able to back out the efficiency based off the spec output and planform area.
The short answer is no, you really don't have the equipment to calculate it based off the power output from a light bulb. You would have a much more accurate answer of simply looking up the specs for the type of solar panel you own, and how old it is (some types degrade over time). You might also be able to back out the efficiency based off the spec output and planform area.
