The resistance of a Light Dependent Resistor (LDR) is indeed affected by the wavelength of light incident upon it. The LDR's resistance varies with the intensity of the light falling on it, and different wavelengths of light can have varying effects on its resistance.
LDRs are typically made of semiconductor materials that exhibit a property called photoconductivity. Photoconductivity refers to the increase in electrical conductivity of a material when exposed to light. In the case of an LDR, the resistance decreases as the intensity of light increases.
Regarding the specific effect of wavelength, it depends on the specific characteristics of the LDR material. Different materials used in LDRs have different sensitivities to different wavelengths of light. Some LDRs may be more sensitive to shorter wavelengths (such as blue or ultraviolet light), while others may be more sensitive to longer wavelengths (such as red or infrared light).
This sensitivity to specific wavelengths occurs because the bandgap of the semiconductor material determines the energy required to promote an electron from the valence band to the conduction band. Different wavelengths of light carry different amounts of energy, and if the energy of a photon matches or exceeds the bandgap energy, it can excite electrons into the conduction band, thereby reducing the resistance.
In summary, the relationship between the wavelength of incident light and the resistance of an LDR depends on the specific properties of the LDR material. The resistance typically decreases as the intensity of light increases, but the exact wavelength dependence varies based on the composition and bandgap of the semiconductor material used in the LDR.