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Two idential pith balls , each of mass m and charge +q. are suspended from a point with threads of lengthl each. If in equiilbrium statetheta be the angle which each thread makes with vertical in equilibrium , find value of charge on each ball. |
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Answer» Solution :The EQUILIBRIUM state is shown in following Forces ACTING on EITHER ball are (i)Weight mg in vertically downward direction. (ii)Coulombian force ` F= (1)/(4 pi in _0) . (Q^(2))/((AB)^(2)) = (1)/( 4 pi in _0).( q^(2))/(4 l ^(2) sin ^(2) theta)`in horizontal direction, and (iii)Tension in thread T. In equilibrium state ` T cos theta = mg ""...(i) ` and ` "" T sin theta =F= (q^(2))/( 4 pi in _0. 4 l^(2)sin ^(2) theta ) ""...(ii )` `rArr ""tan theta =( q^(2))/(4 pi in _0 . 4l^(2) sin ^(2) theta. mg) ` or ` ""q= 2l sin theta sqrt( 4 pi in_0 mg. tan theta ) ` ` (##U_LIK_SP_PHY_XII_C01_E10_007_S01.png" width="80%"> |
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