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

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SUMMARY

This discussion focuses on the impact of different light wavelengths on the output of a Light Dependent Resistor (LDR) in plant growth lamps. The experiment involves using a lamp with colored filters to control the wavelength and employing a Cadmium Sulfide (CdS) cell as the standard LDR. Key considerations include the distance between the light source and the LDR, which affects photon flux, and the placement of filters to optimize light exposure. The formula P=VI is utilized to measure power output using an ammeter and voltmeter.

PREREQUISITES
  • Understanding of Light Dependent Resistors (LDRs) and their operation
  • Familiarity with the principles of light wavelength and photon flux
  • Knowledge of basic electrical measurements using ammeters and voltmeters
  • Experience with experimental design and data collection methods
NEXT STEPS
  • Research the effects of specific light wavelengths on plant growth
  • Learn about the characteristics and applications of Cadmium Sulfide (CdS) cells
  • Investigate methods for measuring photon flux in experimental setups
  • Explore the impact of filter placement on light intensity and quality
USEFUL FOR

Students conducting research on plant growth, educators in biology and physics, and anyone interested in the practical applications of light wavelengths in horticulture.

Alecdrew
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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"
 
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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.
 
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