$A$ straight wire of resistance $18 \Omega$ is bent in the form of an equilateral triangular loop. The effective resistance between any two vertices of the triangle is (in $\Omega$)

As shown in the figure,$13$ resistors each of resistance $R$ are connected. The effective resistance between points $A$ and $B$ is:

$A$ wire of length $l$ and resistance $100 \Omega$ is divided into $10$ equal parts. The first $5$ parts are connected in series while the next $5$ parts are connected in parallel. The two combinations are again connected in series. The resistance of this final combination is: (in $\Omega$)

$A$ circular coil of total resistance $40 \Omega$ has two points '$P$' and '$Q$' on its circumference. The arc length between '$P$' and '$Q$' is such that the coil is divided into two parts with resistances $30 \Omega$ and $10 \Omega$. These points are connected to a $16 \text{ V}$ battery with an internal resistance of $0.5 \Omega$. What is the value of the current '$I$' flowing through the circuit (in $\text{ A}$)?

Twelve resistors each of resistance $16 \,\Omega$ are connected in the circuit as shown. The net resistance between $A$ and $B$ (any two conjugate points of the outer square) is ............... $\Omega$.

If the resistivity of all four wires connected in parallel is different as shown in the figure,and all other dimensions of the wires are the same,then the total current $i$ is (the resistance of a wire having resistivity $\rho$ is $R_0$):