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Consider the potentiometer circuit arranged as in figure.The petentiometer wire is 600cm long.(a) At wht distance from the point A should the jockey touch the wire to get zero deflection in the galvanometer?(b) If the jockey touches the wire at a distance of 560cm from A, What will be the current in the galvanometer? |
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Answer» Solution :Resistance per unit LENGTH = 15r/6 For length x, rx = 15rx/6 For the loop PASQ ` (i_1 +i_1) 15/6 rx+ 15/6 r(6-x) i_1 + i_1 r = epsilon ………….(i) ` for the loop awtm, ` i_2r- 15/6 rx (i_1 + i_1) = epsilon /2 ` ` rArri_2 + 15/6 rx (i_1 + i_1) = epsilon /2 ...........(ii) ` For zero DEFLECTION in galvanometer, `i_2 =0` . ` 15/6 rx. i_1 = epsilon /2 ` ` rArr i_1 = epsilon/5.r ` ` Putting i_1 = epsilon/5.r ` ` and i_2 = 0 in eqn. (i) ` ` we get, x = 320 cm. ` `(B) Putting x = 5.6 and solving equation` ` (i) & (ii) ` ` we get,i_2 = 2epsilon/ 22r ` . |
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