When a wire of uniform cross-section $a$,length $l$ and resistance $R$ is bent into a complete circle,what is the resistance between any two diametrically opposite points?

In the circuit diagram shown,each battery is ideal having an e.m.f. of $1\ V$. Each resistor has a resistance of $1\ \Omega$. The ammeter $(A)$ has a resistance of $1\ \Omega$. Find the reading of the ammeter and the total thermal power produced in the circuit.

All wires have the same resistance $r$. The equivalent resistance between $A$ and $B$ is $R$. Now,if the keys $K_1$ and $K_2$ are closed,what will be the new equivalent resistance?

In the circuit shown,the variable resistance is adjusted such that the ammeter reading is the same in both positions $1$ and $2$ of the key. The reading of the ammeter is $2 \, A$. If $E = 20 \, V$,then $x$ is: ................... $\Omega$

In the given circuit,the $5\, \Omega$ resistor dissipates $45\, J/s$ of heat due to the current flowing through it. The power dissipated per second in the $12\, \Omega$ resistor will be .............. $W$.

In the adjoining circuit,the potential difference across $3\,\Omega$ is ................ $V$.