In a metre-bridge,when a resistance in the left gap is $2 \ \Omega$ and an unknown resistance is in the right gap,the balance length is found to be $40 \ cm$. On shunting the unknown resistance with $2 \ \Omega$,the balance length changes by: (in $cm$)

In a meter bridge or Wheatstone bridge for the measurement of resistance,the known and the unknown resistances are interchanged. The error so removed is

In a metre bridge experiment,the null point is obtained at $20 \,cm$ from the left end of the wire,when resistance $X$ is balanced against another resistance $Y$ $(X < Y)$. To balance a resistance $4X$ against $Y$,the new position of the null point from the same end will be: (in $\,cm$)

Two wires $A$ and $B$ of equal lengths are connected in left and right gap respectively of a metre bridge, null point is obtained at $40 \text{ cm}$ from left end. Diameters of the wires $A$ and $B$ are in the ratio $3:1$ respectively, the ratio of specific resistance of $A$ to that of $B$ is (in $: 1$)

In the experimental setup of a meter bridge shown in the figure,the null point is obtained at a distance of $40\,cm$ from $A$. If a $10\,\Omega$ resistor is connected in series with $R_1$,the null point shifts by $10\,cm$. The resistance that should be connected in parallel with $(R_1 + 10)\,\Omega$ such that the null point shifts back to its initial position is .............. $\Omega$.

In a metre bridge experiment,with a standard resistance in the right gap and a resistance coil dipped in water (in a beaker) in the left gap,the balancing length obtained is $l$. If the temperature of water is increased,the new balancing length is: