MCQ
A group of people watch a ice show which is held in closed area . Skaters perform a . music show whose level is $60\ db$ . Spectator can yell at $40.0 \ dB$ . Which one of the them represent approx combine sound level
- A$65$
- B$50$
- ✓$60$
- D$55$
✓
Answer
Correct option: C.
$60$
c
$\mathrm{I}_{\mathrm{b}}=\left(10^{\frac{40}{10}}\right) 10^{-12}=10^{-3}$
$\mathrm{I}_{\mathrm{b}}=\left(10^{\frac{40}{10}}\right) 10^{-12}=10^{-3}$
$\mathrm{I}_{\mathrm{m}}=\left(10^{6}\right) 10^{-12}=10^{-6}$
${{\rm{I}}_{total}} = {10^{ - 6}}(1 + 0.01) = 1.01 \times {10^{ - 6}}$
$\mathrm{B}_{\text {total }}=10 \log \left(\frac{1.01 \times 10^{-6}}{10^{-12}}\right)=10 \log \left(1.0+10^{6}\right)$
$=10[6+\log 1.01]=60.04$
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