Question

A pendulum having a negatively charged metal knob is oscillating on a positively charged surface. The time of the pendulum will be:

• A. Increase
• B. Decrease
• C. Will remain the same
• D. Will increase and then decrease

Hint:

External forces, such as electric or magnetic forces, can alter the oscillation characteristics of a pendulum.

Answer 1

The Correct Option is B

When a charged pendulum oscillates over a charged surface, the force of attraction between the oppositely charged surfaces increases the effective restoring force. This leads to: \begin{itemize} \item A higher restoring force, which increases the angular frequency \( \omega = \sqrt{\frac{g}{L}} \), \item A decrease in the time period \( T = \frac{2\pi}{\omega} \). \end{itemize} Thus, the pendulum oscillates faster, resulting in a shorter time period. ---