Q. a set $f$ ' $n$ ' identical resistors each of resistance $R$ ohm when connected in reries have a effective resistance of $x$ ohms and when connected in parallel the effective resistance of $Y$ ohms. Then the relation between $R, X$ and $Y$ is

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A

$R=\sqrt{X Y}$

B

$R=Y \sqrt{X}$

C

$R=X \sqrt{Y}$

D

$\sqrt{R}=X Y$

Solution:

WKT $R_{s}=n R $
$R_{P}=R / n$
$X=n R $
$Y=R / n$
$X Y=R^{2}$
therefore $R=\sqrt{X} Y$

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