If the intensity of a sound is mathematically increased by a factor of 100, its loudness level in decibels (dB) increases strictly by: MCQ with Answer and Explanation

If the intensity of a sound is mathematically increased by a factor of 100, its loudness level in decibels (dB) increases strictly by:
A. 100 dB
B. 10 dB
C. 2 dB
D. 20 dB
Answer: Option D
Solution (By JKSSB Mock Tests)
The loudness level in decibels is calculated as L = 10 * log10(I / I0). If intensity I becomes 100I, the new level L' = 10 * log10(100I / I0) = 10 * [log10(100) + log10(I / I0)] = 10 * [2 + L/10] = 20 + L. Therefore, the loudness explicitly increases by 20 dB.

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