Step 1: Concept
The time period \( T \) of a simple pendulum is given by the formula:
\[T = 2\pi \sqrt{\frac{l}{g}}\]
where \( l \) is the length of the pendulum and \( g \) is the acceleration due to gravity.
Step 2: Meaning
This means that the time period depends on the square root of the length of the pendulum. If we increase the length, the time period will also increase proportionally according to this relationship.
Step 3: Analysis
Given:
Original length: \( l \)
Original time period: \( T = 2\pi \sqrt{\frac{l}{g}} \)
When the length is increased to \( 4l \):
\[T_{\text{new}} = 2\pi \sqrt{\frac{4l}{g}}\]
We can simplify this expression:
\[T_{\text{new}} = 2\pi \sqrt{4} \cdot \sqrt{\frac{l}{g}}\]
\[T_{\text{new}} = 2\pi \cdot 2 \cdot \sqrt{\frac{l}{g}}\]
\[T_{\text{new}} = 2 \cdot (2\pi \sqrt{\frac{l}{g}})\]
\[T_{\text{new}} = 2T\]
Thus, the new time period is twice the original time period.
Step 4: Conclusion
The time period of a simple pendulum increases proportionally with the square root of its length. When the length is quadrupled, the time period doubles.
Final Answer: (A)