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Physics · PYQ NEET UG 2016(1)
हिन्दीA potentiometer wire is \( 100\text{ cm} \) long and a constant potential difference is maintained across it. Two cells are connected in series first to support one another and then in opposite direction. The balance points are obtained at \( 50\text{ cm} \) and \( 10\text{ cm} \) from the positive end of the wire in the two cases. The ratio of emf's is
Correct answer · Option 2
3 : 2
Explanation
Using \( \frac{E_1 + E_2}{E_1 - E_2} = \frac{l_1}{l_2} = \frac{50}{10} = 5 \), we get \( E_1 + E_2 = 5E_1 - 5E_2 \implies 6E_2 = 4E_1 \implies \frac{E_1}{E_2} = \frac{3}{2} \).
