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A 10 m long wire of uniform cross-section and 20Omegaresistance is used in a potentiometer. The wire is connected in series with a battery of 5 V along with an external resistance of 480 2. If an unknown emf E is balanced at 6.0 m length of the wire, calculate(i) the potential gradient of the potentiometer wire, (ii) the value of unknown emf. |
Answer» Solution : Here resistance of potentiometer wire `r = 20 Omega , epsi 5V , R = 480 Omega " and " L = 10 m` ` therefore ` POTENTIAL GRADIENT of the potentiometer wire `K = ((epsi.r)/((R+r)).L)` ` = (5 xx 20)/((480 + 20) xx 10)` `= 2 xx 10^(-2) V//m` (ii) Value of unknown emf `E = kl = 2 xx 10^(-2) xx 6 = 0.12 V` |
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