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The potentiometer wire `AB` is `600` cm long. a. At what distance from A should be jockey `J` touch the wire to get zero deflection i the galvanometer. b. If the jockey touches the wire at a distance `560 cm` from A, what will be the current through the galvanometer. |
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Answer» Correct Answer - (a)` 320 cm`(b)` (3E)/(8r)` Current through potentiometer wire `I = (E )/(15 r + r) = (E )/(16 r)` potential drop across potentiometer wire `= (E )/(16 r) xx 15 r = (15E )/(16)` potential gradient of potentiometer wire `K = (15 E//16)/(600) "volt"//cm` (a) UIf galvanometer shown zero deffiection at length `l` of potentiometer wire , then `(E )/(2) = K1 = (15 E)/(16 xx 600)I` `or l = (16 xx 600)/(15 xx 2) = 320 cm` (b) Fall of potential across the length `560 cm = K xx 560` volt .If `l` is the current through galvanometer arm , then `K xx 560 - (E )/(2) = I r or (15 E)/(16 xx 600) xx 560 - (E )/(2) = I r ` `or I = (3E)/(8r)` |
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