In Melde's experiment , when a string is stretched by a piece of glass it vibrates with ` 7 loops` . When the glass piece is completely immersed in water the string vibrates in ` 9 loops`. What is the specific gravity of glass ?

Explanation

To find the specific gravity of glass using the information from Melde's experiment, we can follow these steps:

### Step 1: Understand the relationship between the number of loops and frequency
In Melde's experiment, the number of loops formed on the string is directly related to the frequency of vibration. The frequency of vibration is given by the formula:
\[ f \propto n \]
where \( n \) is the number of loops. Therefore, we can say:
- When the glass is in air (7 loops): \( f_1 \propto 7 \)
- When the glass is immersed in water (9 loops): \( f_2 \propto 9 \)
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