An electric bulb is rated $220 \mathrm{V}$ and $100 \mathrm{W}$. What is the power consumed by it when operated on $110 \mathrm{V}?$

In the circuit element given here, if the potential at point $B, V_B=0$, then the potentials of $A$ and $D$ are given as

In the figure, a part of circuit is shown:

If the ammeter in the given circuit reads $2 \mathrm{A}$, the resistance $R$ is