In the given figure of a meter bridge experiment,the balancing length $AC$ corresponding to null deflection of the galvanometer is $40 \, cm$. What will be the balancing length if the radius of the wire $AB$ is doubled (in $, cm$)?

Consider a $72\, cm$ long wire $AB$ as shown in the figure. The galvanometer jockey is placed at $P$ on $AB$ at a distance $x\, cm$ from $A$. The galvanometer shows zero deflection. The value of $x$,to the nearest integer,is ..... $cm$.

$(a)$ In a meter bridge,the balance point is found to be at $39.5\; cm$ from the end $A$,when the resistor $Y$ is of $12.5\; \Omega$. Determine the resistance of $X$. Why are the connections between resistors in a Wheatstone or meter bridge made of thick copper strips?
$(b)$ Determine the balance point of the bridge above if $X$ and $Y$ are interchanged.
$(c)$ What happens if the galvanometer and cell are interchanged at the balance point of the bridge? Would the galvanometer show any current?

In a meter bridge,two gaps in the metallic strip are connected by $3 \Omega$ and $9 \Omega$ resistors. What should be the value of the shunt that needs to be added in parallel to the $9 \Omega$ resistor to shift the balancing point by $25 \text{ cm}$ (in $Omega$)?

In the given Wheatstone bridge (meter bridge) circuit,the galvanometer shows zero deflection. The value of the unknown resistance $R$ is ................. $\Omega$.

In a meter bridge experiment,when a nichrome wire is in the right gap,the balancing length is $60 \ cm$. When the nichrome wire is uniformly stretched to increase its length by $20 \%$,and again connected in the right gap,the new balancing length is nearly: (in $cm$)