Working of Light Dependent Resistor

It would be great if some could tell what exactly is the principle behind LDR.

Basically, LDR is an electronic component which is sensitive to light. As the intensity of light increases the electrons within LDR start getting more active. Therefore since there are more electrons the resistance decreases which the LDR had. Similarly if there is no light falling upon the LDR, The resistance will be quite high.

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We can say the principle behind the LDR is based on the Internal PhotoElectric effect. When the light is absorbed by the material the conductivity of the material increases i.e the electrons in the valency band are excited to the conduction band and so the resistance decreases.

The working principle of an LDR is photoconductivity, which is nothing but an optical phenomenon. When the light is absorbed by the material then the conductivity of the material enhances .An electronic component like LDR or light-dependent resistor is responsive to light. Once light rays drop on it, then immediately the resistance will be changed. The resistance values of an LDR may change over several orders of magnitude. The resistance value will be dropped when the light level increases.

Hello, I am Sanjeevni,
The answer is:
LDR works on the principle of photoconductivity which is an optical phenomenon.
When material absorbs light , the conductivity of material enhances.
When light falls on LDR , the photons in the incident light must have energy superior to bandgap of the material to make electrons jump from valence to conduction band.
Hence, when light having ample energy, more electrons are excited to the conduction band which grades in a large number of charge carriers. When the effect of this process and the flow of the current starts flowing more, the resistance of the device decreases.