In an electric circuit, a call of certain emf provides a potential difference of 1 . 25   V across a…

In an electric circuit, a call of certain emf provides a potential difference of 1.25 V across a load resistance of 5 Ω. However, it provides a potential difference of 1 V across a load resistance of 2 Ω.The emf of the cell is given by x10 V. Then the value of x is            .

Solution

Terminal voltage, v=iR=ERR+r

1st→1.25=E(5)5+r  …i
2nd→1=E(2)2+r  …ii

By i and ii,
r=1 Ω, E=32 V=1510 volt
⇒x=15

Asked in: JEE Main 2021 (22 Jul Shift 1)

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