The meter bridge shown is in a balanced position with $\frac{P}{Q} = \frac{l_{1}}{l_{2}}$. If we now interchange the positions of the galvanometer and the cell,will the bridge work? If yes,what will be the balance condition?

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 $.......\Omega$.

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

$A$ meter bridge is set up as shown to determine the end corrections at $A$ and $B$. When a resistance of $15\,\Omega$ is used in the left gap and $20\,\Omega$ in the right gap,the null point is obtained at a distance of $42\,cm$ from $A$. When these resistances are interchanged,the null point is obtained at a distance of $57\,cm$ from $A$. The values of the end corrections are:

In the meter bridge shown,the length $AB$ for which the deflection in the galvanometer is zero will be ............. $cm$.

$A$ resistance of $2\,\Omega$ is connected across one gap of a meter-bridge and an unknown resistance,greater than $2\,\Omega$,is connected across the other gap. When these resistances are interchanged,the balance point shifts by $20\,cm$. Neglecting any end correction,the unknown resistance is ................ $\Omega$.