If each resistance in the figure is $9 \Omega$,then the reading of the ammeter $(A)$ is (in $A$)

When an ammeter of negligible internal resistance is inserted in series with the circuit,it reads $1 \, A$. When a voltmeter of very large resistance is connected across $X$,it reads $1 \, V$. When points $A$ and $B$ (across $Y$) are shorted by a conducting wire,the voltmeter measures $10 \, V$ across the battery. The internal resistance of the battery is equal to .............. $\Omega$.

Thirteen resistances,each of resistance $R \, \Omega$,are connected in the circuit as shown in the figure below. The effective resistance between $A$ and $B$ is

In the circuit shown,the potential difference between $X$ and $Y$ will be ............. $V$.

The equivalent resistance between $x$ and $y$ in the circuit shown is ............. $\Omega$

The effective resistance between points $P$ and $Q$ of the electrical circuit shown in the figure is