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Per NCERT Activity 9.2, why does paper held at the focus of a CONCAVE MIRROR pointed at the sun catch fire?
ASunlight is hot enough on its own
BPaper burns randomly
CConvex mirror would be needed
DConcave mirror converges parallel sun rays to a SHARP focal point — concentrated sunlight there ignites the paper
Answer & Solution
Correct answer: D. Concave mirror converges parallel sun rays to a SHARP focal point — concentrated sunlight there ignites the paper
Per NCERT Activity 9.2, concentrated sunlight at the focal point ignites paper. Also used in solar furnaces.
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