Four identical resistors are connected in series with a battery,dissipating $20 \ W$ of power. What will be the power dissipated if the same resistors are connected in parallel to the same battery (in $W$)?

Find the equivalent resistance between point $A$ and $B$ in the following circuit. (The resistance of each resistor is $R$)

$A$ uniform wire of resistance $20 \,\Omega$ having resistance $1 \,\Omega/m$ is bent into a circle as shown in the figure. If the equivalent resistance between $M$ and $N$ is $1.8 \,\Omega$,then the length of the shorter section is ................ $m$.

Let there be $n$ resistors $R_1, \dots, R_n$ with $R_{\max} = \max \{R_1, \dots, R_n\}$ and $R_{\min} = \min \{R_1, \dots, R_n\}$. Show that when they are connected in parallel,the resultant resistance $R_p < R_{\min}$ and when they are connected in series,the resultant resistance $R_s > R_{\max}$. Interpret the result physically.

$A$ wire of resistance per unit length $\rho_L = 10^{-6} \, \Omega/m$ is bent into a circle of diameter $2 \, m$. $A$ piece of wire of the same material is connected across the diameter $AB$. Find the resistance between $A$ and $B$.

Eight resistances each of resistance $5\,\Omega$ are connected in the circuit as shown in the figure. The equivalent resistance between $A$ and $B$ is