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

An infinite sequence of resistors is shown in the figure. The resultant resistance between $A$ and $B$ will be,when $R_1 = 1\,\Omega$ and $R_2 = 2\,\Omega$ ............. $\Omega$

When the terminals of a cell are connected by a wire of resistance $4 \Omega$,the potential difference across the cell is $1.6 \text{ V}$. If a wire of the same resistance is connected in parallel with the first,the potential difference becomes $1.33 \text{ V}$. The emf and internal resistance of the cell are respectively

$B_{1}$, $B_{2}$ and $B_{3}$ are three identical bulbs connected to a battery of steady $EMF$ with key $K$ closed. What happens to the brightness of the bulbs $B_{1}$ and $B_{2}$ when the key $K$ is opened?

In the circuit shown,the variable resistance is adjusted such that the ammeter reading is the same in both positions $1$ and $2$ of the key. The reading of the ammeter is $2 \, A$. If $E = 20 \, V$,then $x$ is: ................... $\Omega$

In the circuit shown,the galvanometer $G$ of resistance $60 \, \Omega$ is shunted by a resistance $r = 0.02 \, \Omega$. The current through $R$ is nearly $1 \, A$. The value of resistance $R$ (in $\Omega$) is nearly: