How Does Light Wavelength Affect LDR Output in Plant Growth Lamps?

[Alecdrew]

Homework Statement

it is a reasearch project i have to plan an experiment to find what effect different wavelengths of light, from a lamp which is used to grow plants, will have on the output of an LDR.

Homework Equations

The Attempt at a Solution

so far my plan is (breifly) to use a lamp and put coloured filters in front of it to controll the wavelength. also i have researched a CdS cell which would be the standard lab LDR i will use. The only thing i really need help with is a proximate ranges for meters required. as i have bin looking for days and can't find anything that would help, i am using an ammeter and voltmeter to give the power output. "P=VI"

 

[Astronuc]

The only thing i really need help with is a proximate ranges for meters required.

The distance between light source and LDR (light dependent resistor) would determine the number of photons arriving at the LDR, by virtue of the area * photon flux.

One could start some distance away from the light source and gradually move the LDR closer and measure the response or signal strength.


This might provide some insight - http://www.doctronics.co.uk/ldr_sensors.htm

The filtering will also affect the flux since it will 'filter out' some fraction of the photons. It would perhaps be better to place the filter nearer to the detecting LDR rather than the source.

 

[m2003]

I would first suggest conducting a thorough literature review on the topic to gather background information and see if similar experiments have been done before. This will help you determine the appropriate range for your meters and also provide insight on potential variables that could affect your results.

In terms of your experiment design, it is important to consider controlling for other factors such as the distance between the lamp and the LDR, the intensity of the light, and the angle of the light hitting the LDR. These variables can greatly impact the output of the LDR and should be carefully controlled.

Additionally, you may want to consider using a spectrophotometer to measure the specific wavelengths of light being emitted by the lamp and determine the exact wavelengths you want to test. This will ensure accuracy and precision in your results.

Finally, I would recommend conducting multiple trials for each wavelength and taking the average of the results to reduce the impact of random error. Overall, your proposed experiment is a good starting point, but it is important to carefully consider all variables and plan for potential limitations to ensure reliable and accurate results.