In the given circuit,the current flowing through the resistance $20 \ \Omega$ is $0.3 \ A$,while the ammeter reads $0.9 \ A$. The value of $R_1$ is . . . . . . $\Omega$.

Four wires $AB, BC, CD, DA$ of resistance $4\, \Omega$ each and a fifth wire $BD$ of resistance $8\, \Omega$ are joined to form a rectangle $ABCD$,where $BD$ is a diagonal. The effective resistance between the points $A$ and $B$ is:

There are three resistance coils of equal resistance. The maximum number of distinct equivalent resistances you can obtain by connecting them in any manner you choose,being free to use any number of the coils in any way,is

Six wires, each of resistance $r$, are connected so as to form a tetrahedron. The equivalent resistance of the combination when current enters through one corner and leaves through some other corner is

$A$ wire of resistance $12 \, \Omega$ is bent to form an equilateral triangle. What is the equivalent resistance between any two corners of the triangle?

$A$ ring is made of a wire having a resistance $R_0 = 12\,\Omega$. Find the ratio of the lengths $\frac{l_1}{l_2}$ of the two arcs between points $A$ and $B$ as shown in the figure,such that the equivalent resistance $R$ of the sub-circuit between these points is equal to $\frac{8}{3}\,\Omega$.