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An electrometer consister of a fixed ver...

An electrometer consister of a fixed vertical metal bar OB at the top of which is attached a thin rod OA which gets deflected from the bar under the action of an electric charge (fig.). The rod can rotate in vertical plane about fixed horizontal axis passing through O. The reading is taken on a quadrant graduated in degrees. The length of the rod is `l` and its mass is m. what will be the charge when the rod of such an electrometer is deflected through an angle `alpha` in equilibrium. Find the answer using the following two assumptions :
The charge on the electrometer is equally distributed between the bar & the rod and the charges are concentrated at point A on the rod & at point B on the bar.

Text Solution

Verified by Experts

The correct Answer is:
`q=4l sqrt(4pi in_(0) mg sin (alpha/2))" sin "alpha/2`
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Knowledge Check

  • A uniform metal rod is rotated in horizontal plane about a vertical axis passing through its end at uniform rate. The tension in the rod is

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