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Question
Two particles, carrying charges −q and +q and and of mass m each, are fixed at the ends of a light rod of length a to form a dipole. The rod is clamped at an end and is placed in a uniform electric field E with the axis of the dipole along the electric field. The rod is slightly tilted and then released. Neglecting gravity, find the time period of small oscillations.
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Solution
Consider the rod to be a simple pendulum
Time period of a simple pendulum,
(where l = length and a' = acceleration)
Now
∴ The time period,
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