The potential difference between point $A$ and $B$ is ............. $V$.

The reading of the ammeter $(A)$ in steady state in the following circuit (assuming negligible internal resistance of the ammeter) is . . . . . . $A$.

In the given circuit,$(V_A - V_B) = \dots \dots \dots V$.

Two batteries $A$ and $B$, each of e.m.f. $2 \, V$, are connected in series to an external resistance $R = 1 \, \Omega$. If the internal resistance of battery $A$ is $1.9 \, \Omega$ and that of $B$ is $0.9 \, \Omega$, what is the potential difference between the terminals of battery $A$?

The series combination of two batteries,both of the same emf $10 \; V,$ but different internal resistances of $20 \; \Omega$ and $5 \; \Omega,$ is connected to the parallel combination of two resistors $30 \; \Omega$ and $R \; \Omega.$ If the voltage difference across the battery of internal resistance $20 \; \Omega$ is zero,the value of $R$ (in $\Omega$) is:

When a resistance of $9 \,\Omega$ is connected across the terminals of a battery,its potential difference decreases from $40 \, V$ to $30 \, V$. The internal resistance of the battery is ............... $\Omega$.