A potentiometer circuit shown in the figure is set up to measure $e.m.f.$ of a cell $E$. As the point $P$ moves from $X$ to $Y$ the galvanometer $G$ shows deflection always in one direction, but the deflection decreases continuously until $Y$ is reached. In order to obtain balance point between $X$ and $Y$ it is necessary to
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(a) Decreasing $R$ increases current in $XY$ and there by increases the potential drop across $XP$ and the balance point may be obtained. The current may be increased also by increasing $V.$
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