Resistances are connected in a meter bridge circuit as shown in the figure. The balancing length $l_{1}$ is $40\,cm$. Now an unknown resistance $x$ is connected in series with $P$ and the new balancing length is found to be $80\,cm$ measured from the same end. Then the value of $x$ will be $.......\Omega$.

Two resistances are connected in two gaps of a meter bridge. The balance point is $20 \ cm$ from the zero end. $A$ resistance of $15 \ \Omega$ is connected in series with the smaller of the two. The null point shifts to $40 \ cm$. The value of the smaller resistance in $\Omega$ is

When a wire is connected in the left gap of a metre bridge,the balancing point is at $40 \ cm$ from the left end of the bridge wire. If the wire in the left gap is stretched so that its length is doubled and again connected in the same gap,then the balancing point from the left end of the bridge wire is

In a meter bridge experiment,initially the jockey is at the null point. Now,resistances $R_1$ and $R_2$ are interchanged. The shift in the position of the jockey is ................ $cm$.

In a sensitive meter bridge apparatus,the bridge wire should possess:

In a meter bridge experiment, the balance point is obtained at length $\ell_1 \, cm$ from the left end when resistances in the left gap and right gap are $5 \, \Omega$ and $R \, \Omega$ respectively. When the resistance $R$ is shunted with an equal resistance, the new balance point is at $1.6 \ell_1$. The resistance $R$ in ohm is