Many veteran rockers suffer from acute hearing damage because of the high sound levels they endured for years. Many rockers now wear special earplugs to protect their hearing during performances . If an earplug decreases the sound level of the sound waves by 20 dB, what is the ratio of the final intensity `I_f` of the waves to their initial intensity `I_i` ?

Explanation

To solve the problem of finding the ratio of the final intensity \( I_f \) of the sound waves to their initial intensity \( I_i \) after a decrease of 20 dB, we can follow these steps:

### Step 1: Understand the relationship between sound level in decibels and intensity
The sound level \( L \) in decibels is given by the formula:
\[ L = 10 \log_{10} \left( \frac{I}{I_0} \right) \]
where:
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