In a post office box arrangement used to determine the value of an unknown resistance,the unknown resistance should be connected between:

The current flowing through the circuit shown in the figure is ............ $A$.

In the following figure, the current $I$ is equal to: (in $\text{ A}$)

In the given circuit diagram,a wire is joining points $B$ and $D$. The current in this wire is ............. $A$.

$A$ uniform wire of length $200 \, cm$ is connected to a battery, two resistors and a galvanometer as shown in the figure. The galvanometer shows null deflection when the jockey $J$ is at $80 \, cm$ from point $A$. If the resistor $R_2$ is shunted with $30 \, \Omega$ resistance, the galvanometer shows null deflection when the jockey $J$ is at $100 \, cm$ from point $B$. Then the values of $R_1$ and $R_2$ respectively are

For the given circuit,the currents $I$ and $I_2$ are respectively: