Question

The time period of a simple pendulum is 2 sec. If its length is increased 4 times, then its period becomes

• A. 16 sec
• B. 12 sec
• C. 8 sec
• D. 4 sec

Answer 1

Answer: (D)

4 sec

Answer 2

$T \propto \sqrt{l}$⇒ $\frac{T_{1}}{T_{2}} = \sqrt{\frac{l_{1}}{l_{2}}}$ ⇒ $\frac{2}{T_{2}} = \sqrt{\frac{l}{4l}}$ ⇒ $T_{2} = 4sec$