Difficulty: Easy
Correct Answer: solar cell
Explanation:
Introduction / Context:Many electronic components respond to light, but only certain devices are intended to convert light energy directly into electrical power. Distinguishing among light-sensitive components is key for selecting parts in energy-harvesting and sensing applications.
Given Data / Assumptions:
Concept / Approach:A solar cell (photovoltaic cell) generates a voltage and current when illuminated via the photovoltaic effect. Photodiodes and phototransistors are light sensors optimized for signal detection, typically requiring bias and producing small currents; they are not intended primarily as power sources. A thermocouple converts temperature differences to voltage via the Seebeck effect, not light directly.
Step-by-Step Solution:
1) Identify device with photovoltaic effect: the solar cell.2) Contrast with photodiode/transistor: mainly sensing, not power generation.3) Exclude thermocouple: converts heat gradients, not light.Verification / Alternative check:Solar panels, which are series/parallel assemblies of solar cells, are ubiquitous proof of light-to-electric power conversion at practical scales.
Why Other Options Are Wrong:
Thermocouple: temperature-to-voltage, unrelated to light.Photodiode: primarily a sensor; produces small photocurrents, not generally used as a power source.Photo transistor: light-controlled transistor, again a sensor/amplifier, not a power generator.None of the above: incorrect because solar cell is correct.Common Pitfalls:Assuming all light-sensitive devices are interchangeable; confusing photovoltaic effect (power) with photoconductive or phototransistor sensing (signal).
Final Answer:solar cell.
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