do colored light filters give you a single wavelength range?

I need to do a science project, and I need to measure the photovoltaic effect of different wavelength of light on my solar cell with a voltmeter. I am trying to set this up using a small spotlight for a disco ball, using the color filters that comes with it. Will this work? I am trying to see what color has most energy in it, and the science fair is NEXT WEEK HELP

There are two ways for a color filter to make the light look green. It can either just pass green light, which will means it restricts the light to a single range (the green range). Or it can pass blue and yellow light, which means it will restrict it to two ranges. Because of the way your eye works, there is no way to tell based solely on looking at the color. However, there are ways to tell. What you should do is get a prism (those little glass wedges… some cut glass crystal like from a chandelier will also work, but not as well) and shine the light into that. The prism will split light by its wavelength or color, so that white light comes out looking like a rainbow. If you put true green light in, then you will only get green light out. If you put blue and yellow light that looks green in, then you will get a blue and a yellow band of light out. Chances are your filters will be a mix of these two colors.

Now if you have such a prism, an easier way to get monochromatic (one color) light is to shine white light into the prism. That will separate the colors into a rainbow. Then if you take a piece of cardboard and cut a slot in it, you can let the rainbow of light hit that slot. If you orient the slot in the right way, you can only let a single color through while blocking the other colors. That color that gets through will be very close to monochromatic. But to do this and get a lot of light, you will need a very bright white light to start out with.

Ok, now that I have said that, let me clue you in on an issue that will plague both my idea and your idea. These different colors of light, be they from using my prism or your filter, will have different powers. With the prism, the power, or intensity will depend on how much power there is in each band of light in the white light source. With the filters, it will depend both on that and on how dark the filter is. And you will get more power from a solar cell when you have more light. So you might think that one color has more energy per photon because you get more power, but it might just be that there is more of that light in your source. And this is the type of thing that can not be judged just using your eye, because your eye is also more sensitive to some colors (green) than others (red). However, if you connect correctly to your solar cell, you may notice a difference in the voltage you get from each color and that voltage should not be intensity dependent, just color dependent. My point is you might have to think carefully about what you are measuring and whether or not it is being influenced by things you don’t intend to measure.

Good luck with your experiment.

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