How do solar panels convert light energy into electrical energy, and what is a limitation?

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Multiple Choice

How do solar panels convert light energy into electrical energy, and what is a limitation?

The key idea is the photovoltaic effect: light energy is converted to electricity by a semiconductor in a solar cell. When photons hit the cell, they transfer their energy to electrons in the material, creating electron–hole pairs. The built-in electric field at the p–n junction separates these charges, pushing electrons toward one side and holes toward the other, which establishes a voltage. When the cell is part of a circuit, electrons flow, delivering electrical energy. There are no moving parts, and the energy comes directly from light. A practical limitation is that solar cells aren’t perfectly efficient. Some light is reflected, some energy is lost as heat when excited electrons relax, and not all photons have the right energy to create charge carriers. Plus, sunlight availability varies with time of day, weather, and shading, so output fluctuates.

The key idea is the photovoltaic effect: light energy is converted to electricity by a semiconductor in a solar cell. When photons hit the cell, they transfer their energy to electrons in the material, creating electron–hole pairs. The built-in electric field at the p–n junction separates these charges, pushing electrons toward one side and holes toward the other, which establishes a voltage. When the cell is part of a circuit, electrons flow, delivering electrical energy. There are no moving parts, and the energy comes directly from light.

A practical limitation is that solar cells aren’t perfectly efficient. Some light is reflected, some energy is lost as heat when excited electrons relax, and not all photons have the right energy to create charge carriers. Plus, sunlight availability varies with time of day, weather, and shading, so output fluctuates.

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