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:

In the circuit shown,the current through $R_2$ is zero. If $R_4 = 2\,\Omega$ and $R_3 = 4\,\Omega$,the current through $R_3$ will be ................. $A$.

Three voltmeters,all having different internal resistances,are connected as shown in the figure. When a potential difference is applied across $A$ and $B$,their readings are $V_1, V_2$,and $V_3$. Choose the correct option.

$A$ uniform metallic wire having resistance $4 \ \Omega$ is bent to form a square loop $(ABCD)$ (see figure). $A$ resistance of $2 \ \Omega$ is connected between points $B$ and $D$ and a battery of $2 \ V$ is connected across points $A$ and $C$ as shown in the figure. Now the value of current $(I)$ is: (in $A$)

The readings of the voltmeter and ammeter in the circuit shown in the diagram are respectively

The charge supplied by a source varies with time $t$ as $Q = at - bt^2$. Find the total heat produced in the $2R$ resistor before the current reduces to zero.