Consider two circuits, (A) and (B), each having two resistors. One of them has a positive temperature coefficient of resistance, $+\alpha$, while the other one has a negative temperature of coefficient, $-\alpha$, as shown in the figure. The current through these circuits are denoted by $I_A$ and $I_B$. At initial temperature, the resistance of the two resistors is $R_0$. As the temperature is increased, the correct option that describes the variation of current in these circuits is:

A resistor is connected to a battery of 12 V emf and internal resistance $2 \Omega$. If the current in the circuit is 0.6 A , the terminal voltage of the battery is:

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 $(l)$ is :