What is the equivalent resistance of the circuit in $\Omega$?

As shown,the circuit is made of $8$ different resistors. It is found that when $R_1 = 4\,\,\Omega,$ the resistance between $A$ and $B$ is $2\,\,\Omega.$ Now replace $R_1$ by a $6\,\,\Omega$ resistor,what is the resistance between $A$ and $B$?

Find the potential of point $J$ with respect to point $G$. (in $V$)

In the given figure,the steady state current $I$ is ................. $A$.

One end each of a resistance $r$,a capacitor $C$,and a resistance $2r$ are connected together. The other ends are respectively connected to the positive terminals of batteries $P$,$Q$,and $R$ having emfs $E$,$E$,and $2E$. The negative terminals of the batteries are then connected together. In this circuit,with steady current,the potential drop across the capacitor is:

The current in a simple series circuit is $5.0 \, A$. When an additional resistance of $2.0 \, \Omega$ is inserted, the current drops to $4.0 \, A$. The original resistance of the circuit in $\Omega$ was: