Light Intensity

[JoeParkinson]

If light intensity is inversely proportional to resistance, then light intensity is proportional to current due to V=IR. So will a graph of light intensity v wavelength look the same as current v wavelength.

And can this current just be measured by having and LDR and an ammeter in series with constant voltage? thanks

[Teddio]

A graph of Resistance versus Light Intensity will be a curve of negative gradient. Light Intensity and Wavelength are independent of each other. An LDR, such as an ORP 12, will have a resistance in the dark of about 2 million Ohms and a resistance in bright sunlight of about 80 Ohms. Consequently, your ammeter will have to have a very large range. eg. if your constant voltage is 12 Volts, then the current will range from 0.15A (light) to 6 microamps (dark)