What effect does an increase in light on a photocell have on resistance?

When considering the relationship between light and the resistance of a photocell, it is important to understand the fundamental operation of this device. Photocells, or photoresistors, are typically made from materials whose resistance changes in response to light intensity.

When light levels increase, the energy from the light photons causes more charge carriers (electrons) to be released within the semiconductor material of the photocell, thus allowing more electrical current to flow through the device. As a result, the resistance of the photocell decreases. This response to light is what makes photocells useful in applications such as automatic lighting and solar panels, where they function effectively in varying lighting conditions.

Therefore, understanding that increased light leads to a decrease in resistance is essential for anyone working with or studying instrumentation and sensor technology. The functioning principle of a photocell is directly tied to its changing resistance in response to light intensity.