GS PrelimsScience and TechnologyGeneral Science2009

Which one of the following types of waves are used in a night vision apparatus?

Radio waves

Microwaves

Infra-red waves

None of the above

Correct Answer: Option C

Explanation

1. Night vision apparatus works by detecting and amplifying available light (image intensification) or by detecting heat signatures (thermal imaging). 2. Image intensification amplifies very low levels of visible and near-infra-red light. 3. Thermal imaging detects infra-red radiation (heat) emitted by objects. 4. Therefore, Infra-red waves are crucial for the operation of most night vision devices.

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