A thick wire is stretched, so that its length becomes two times. Assuming that there is no change in its density, then what is the ratio of change in resistance of wire to initial resistance of wire ?

$I-V$ characteristics of a copper wire of length $L$ and area of cross-section $A$ is shown in figure, Fig. $5.176.$ The slope of the curve becomes 

The total current supplied to the given circuit in Fig.$5.177$ By the battery is 

The equivalent resistance between the terminals $A$ and $D$ in the following circuit, in Fig.$5.178$

Six resistance each of value $3\Omega$ Are connected as shown in the figure, Fig. $5.179.$ A cell of emf $3 volt$ Is connected across $AB$. The effective resistance across $AB$ And the current through the arm $AB$ Will be 

Fig.$5.180$ shows a network of eight resistors, each equal to $2\Omega ,$ connected to a $3 V$ battery of negligible internal resistance. The current $I$ in the circuit is 

The equivalent resistance between the points $A$ and $B$ will be (each resistance is $15\Omega$)