The extension in a wire obeying Hooke’s law is \( x \). The speed of sound in the stretched wire is \( V \). If the extension in the wire is increased to \( 4x \), then the speed of sound in the wire is
Show Hint
When dealing with stretched wires, remember that the speed of sound is proportional to the square root of the tension in the wire.
Step 1: Formula for the speed of sound in a stretched wire.
The speed of sound in a wire depends on the tension in the wire and the mass per unit length. The relationship is given by:
\[
V \propto \sqrt{\frac{T}{\mu}}
\]
where \( T \) is the tension and \( \mu \) is the mass per unit length.
Step 2: Relationship between extension and tension.
Since the tension is directly proportional to the extension \( x \), if the extension is increased to \( 4x \), the tension will also increase by a factor of 4. Therefore, the speed of sound will increase by a factor of \( \sqrt{4} = 2 \).
Step 3: Conclusion.
Thus, the new speed of sound is (C) \( 2V \).