Subtopic: Human engineering and safety considerations in design of tractor and agricultural implements
Question Statement:
The RMS sound pressure is increased by 50%. This increases the sound pressure level, in dB, nearly by
Options:
(A) 3.52
(B) 8.11
(C) 100.21
(D) 43.52
Official Answer Key:
A
Step-by-Step Solution & Explanation
Sound pressure level is defined on pressure, so the multiplier is 20, not 10:
SPL = 20 log₁₀(p/p_ref) dB
Increase in level when pressure rises from p to 1.5p:
ΔSPL = 20 log₁₀(1.5p) − 20 log₁₀(p) = 20 log₁₀(1.5)
= 20 × 0.176091 = 3.52 dB
Key distinction: intensity or power levels use 10 log₁₀ (since I ∝ p²); pressure levels use 20 log₁₀. Using 10 log₁₀ here would wrongly give 1.76 dB.
Practice This in Real CBT Exam Interface
Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.