In a meter bridge,the two gaps contain resistances of $10 \, \Omega$ and $30 \, \Omega$ respectively. If these resistances are interchanged,the null point shifts by ..... cm.

When two resistances $R_1$ and $R_2$ are connected in series and introduced into the left gap of a meter bridge and a resistance of $10 \ \Omega$ is introduced into the right gap,a null point is found at $60 \ cm$ from the left side. When $R_1$ and $R_2$ are connected in parallel and introduced into the left gap,a resistance of $3 \ \Omega$ is introduced into the right gap to get a null point at $40 \ cm$ from the left end. The product $R_1 R_2$ is $............. \ \Omega$.

Two resistors $2 \Omega$ and $3 \Omega$ are connected in the gaps of a meter bridge as shown in the figure. The null point is obtained with the contact of the jockey at some point on the wire $XY$. When an unknown resistor $R$ is connected in parallel with the $3 \Omega$ resistor, the null point is shifted by $22.5 \text{ cm}$ toward $Y$. The resistance of the unknown resistor $R$ is . . . . . . $\Omega$.

The unknown resistances are connected in two gaps of a metre bridge. The null point is at $20 \ cm$ 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 smaller resistance is (in $\Omega$)

In a meter bridge,the resistances $R$ and $S$ are such that the null point is found at a distance of $40 \text{ cm}$ from one end. If a resistance of $10 \Omega$ is connected in parallel with shunt $S$,then the null point occurs at $90 \text{ cm}$ from the same end. The values of the two resistances $R$ and $S$ respectively are:

In the given arrangement of the experiment on a meter bridge,if $AD$ corresponding to the null deflection of the galvanometer is $X$,what would be its value if the radius of the wire $AB$ is doubled?