RAS question
Photovoltaic cells convert:
Correct answer: (C) Sunlight directly into electricity.
Photovoltaic cells convert sunlight directly into electricity through the photovoltaic effect in semiconductor material.
Explanation
Photovoltaic cells, also called solar cells, are non-mechanical devices that convert sunlight directly into electricity. The key point is the direction of conversion: light energy from the Sun is the input, and electrical energy is the output. PV cells use semiconductor material, typically silicon, and work through the photovoltaic effect. The EIA explains the same mechanism: photons in sunlight strike the PV cell, and only absorbed photons provide the energy that generates electricity. When the semiconductor absorbs enough solar energy, electrons are dislodged, creating the flow that becomes electric current. That is why the precise answer is sunlight directly into electricity, not heat, motion, or chemical energy.
Why the other options are wrong
- (A) Chemical energy into light describes a chemical-to-radiant conversion, whereas a PV cell starts with sunlight and produces electricity.
- (B) Kinetic energy into heat is a motion-to-thermal conversion, while PV cells use photons from sunlight rather than moving bodies as the input.
- (D) Heat energy into light reverses the relevant idea, because photovoltaic cells convert light energy into electricity rather than producing light from heat.
Concept
This tests the basic science of renewable-energy technology, especially energy conversion in solar photovoltaic systems. It recurs in RAS because solar power is central to environment, energy, and applied science questions.