Resistors of $4\, R, 16\, R, 64\, R, \dots \infty$ are connected in series. Find their equivalent resistance.

Three unequal resistors in parallel are equivalent to a resistance $1 \ \Omega$. If two of them are in the ratio $1:2$ and if no resistance value is fractional,then the largest of the three resistances in ohms is

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 $R_0$):

For the mixed connection shown in the figure,derive the equation for the equivalent resistance.

Find the effective resistance between $A$ and $B$ in the given circuit.

Resistors of $10\, \Omega, 5\, \Omega, 7\, \Omega$, and $3\, \Omega$ are connected along the sides $AB, BC, CD$, and $DA$ of a square, respectively. A resistor of $10\, \Omega$ is connected across the diagonal $AC$. What is the equivalent resistance between points $A$ and $B$ in $\Omega$?