A solar-cell is placed outdoors on a clear day and has an...

A solar-cell is placed outdoors on a clear day and has an output current of $2 \mathrm{~mA}$ at peak sun intensity (noon), and $0.01 \mathrm{~mA}$ when exposed to moonlight. Plot the approximate current output expected versus time over a 24 -hour period, assuming: (a) The solar cell is unobstructed. (b) A cat stands over the solar cell for one hour beginning at noon (assume an opaque cat). (c) A cloud cover comes in at 3:00 PM, reducing the sun's intensity on the solar cell by one-half.

A solar-cell is placed outdoors on a clear day and has an output current of $2 \mathrm{~mA}$ at peak sun intensity (noon), and $0.01 \mathrm{~mA}$ when exposed to moonlight. Plot the approximate current output expected versus time over a 24 -hour period, assuming:
(a) The solar cell is unobstructed.
(b) A cat stands over the solar cell for one hour beginning at noon (assume an opaque cat).
(c) A cloud cover comes in at 3:00 PM, reducing the sun's intensity on the solar cell by one-half.

Key Concepts

Impact of Atmospheric Conditions

Atmospheric conditions like cloud cover can reduce the intensity of sunlight reaching a solar cell. Clouds can diffuse and attenuate sunlight, leading to a decrease in the effective illumination and a consequent drop in current output. Understanding this concept is crucial for modeling and predicting solar cell performance under varying weather conditions.

Effect of Obstructions on Light Exposure

Obstructions can temporarily block or reduce the amount of light reaching a solar cell, thereby diminishing its current output. This concept illustrates that any physical object or barrier (such as a temporary cover) can lead to transient changes in solar cell performance, independent of the natural diurnal light cycle.

Diurnal Variation of Light Intensity

This refers to the natural changes in light intensity over a 24-hour period as the sun rises, reaches its peak, and sets. The intensity is highest near noon when the sun is overhead and diminishes towards the morning and evening, with very low levels during nighttime. These variations directly influence the performance and output current of solar cells throughout the day.

Solar Cell Operation

This concept involves understanding how a solar cell converts light energy into electrical energy. The operation is based on the photovoltaic effect, where incident photons excite electrons in a semiconductor material, generating a current. The efficiency and output of this conversion depend on the intensity and quality of the incident light, as well as the material properties of the cell.

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