Light & Optics MCQs with Answers

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Light is a form of energy and its speed can be measured.

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In a line absorption spectrum, dark lines are due to transmittance — specific wavelengths are absorbed by a cooler gas, leaving dark gaps in the continuous spectrum.

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In photovoltaic cells, the current produced is directly proportional to the intensity of light falling on the cell.

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The flash of light from lightning travels at approximately 3 × 10⁸ m/s, which is the speed of light in a vacuum.

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According to the Beer-Lambert law, absorbance (A) has no unit because it is a logarithmic ratio of incident to transmitted light intensity.

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The correct order of spectral regions with increasing frequency is RF, IR, ViS, UV.

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Monochromatic light passing through a thick prism is deviated (bent) but not dispersed, because dispersion requires multiple wavelengths.

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The signal from a remote control travels with the speed of light because remote controls use infrared radiation, which is a form of electromagnetic wave.

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Mirrors used in car headlights and search lights are concave mirrors because they converge light into a powerful parallel beam.

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Operation theatre spotlights use concave mirrors to focus light into a strong, concentrated beam.