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Question
An I0m long uniform metallic wire having a resistance of 20Ω IS used as a potentiometer wire. This wire is connected in series with another resistance of 480Ω
and a battery of emf 5V having negligible internal resistance. If an unknown emf e is balanced across 6m of the potentiometer wire, calculate
1) the potential gradient across the potentiometer wire
2) the value of the unknown emf e.
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Solution
`l_1 = 10 m`
R = 20 Ω
`R_1 = 480 Ω`
V = 5 V
balancing lenght = `l_2 = 6m`
1) Potential gradient = `k = V/L = 5/6 = 0.83 "V/m"`
2) `E_1/E_2 - l_1/l_2`
`5/E_2 = 10/6`
`5 xx 6 = E_2 xx 10`
`(5 xx 6)/10 = E_2`
`:. E_2 = 3V`
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