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GATE 2024 MN – Question 30

Surface Environment, Mine Ventilation and Underground Hazards · Surface Environment · 1 mark · Numerical answer

Dumper and shovel together produce 95 dB(A) at a point. The shovel alone produces 90 dB(A). Find the dumper-only level in dB(A) to two decimals.

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Correct answer: 93.00 to 94.00

Explanation

Independent sound energies add. Thus the dumper’s energy-proportional intensity is 10^(95/10)−10^(90/10). Its level is 10log₁₀ of that difference, 93.35 dB(A). Directly subtracting 5 dB would not remove the shovel’s energy contribution.

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