Question

Four pendulums $A,B,C$ and $D$ are suspended from the same elastic support as shown in figure. $A$ and $C$ are of the same length, while $B$ is smaller than $A$ and $D$ is larger than $A$. If $A$ is given a transverse displacement,

• A. $D$ will vibrate with maximum amplitude
• B. $C$ will vibrate with maximum amplitude
• C. $B$ will vibrate with maximum amplitude
• D. All the four will oscillate with equal amplitude

Answer 1

Answer: (B)

Since length of pendulums $A$ and $C$ is same and $T=2\pi \sqrt{\frac{L}{g}}$, hence their time period is same and they will have same frequency of vibration. Due to it, a resonance will take place and the pendulum $C$ will vibrate with maximum amplitude.