In the following figure, the current $I$ is equal to: (in $\text{ A}$)

Four resistors $A, B, C$ and $D$ form a Wheatstone bridge. The bridge is balanced when $C = 100 \ \Omega$. If $A$ and $B$ are interchanged,the bridge balances for $C = 121 \ \Omega$. The value of $D$ is: (in $\Omega$)

Kirchhoff's first law,$i.e.$,$\Sigma i = 0$ at a junction,is based on the law of conservation of:

In the given circuit,the electric currents through $15 \Omega$ and $6 \Omega$ resistors respectively are:

$A$ Wheatstone bridge is initially at room temperature and all arms of the bridge have the same value of resistance $(R_1=R_2=R_3=R_4=R)$. When $R_3$ is heated to some temperature, its resistance value increases by $10 \%$. The potential difference $(V_a - V_b)$ (after $R_3$ is heated) is . . . . . . $V$. Given the total voltage is $40 \text{ V}$.

Kirchhoff's first law $(\sum i = 0)$ and second law $(\sum iR = \sum E)$,where the symbols have their usual meanings,are respectively based on: