When the switch K is open, the equivalent resistance between A and B is 20 ohm. Then, which is the correct statement?

Which of the following statements are correct?

1. R = 80 ohm

2. No current flows through K when it is closed.

3. The powers dissipated in R and in the 5 ohm resistor are always equal.

4. The powers dissipated in the two 20 ohm resistors are unequal.

The current in the $1 \mathrm{\Omega }$ resistor shown in the circuit is,

Five equal resistances are connected in a network as shown in figure. The net resistance between the points $A$ and $B$ is :

The four arms of a Wheatstone bridge have resistances as shown in the figure. A galvanometer of $15\Omega$ resistance is connected across BD. Calculate the current through the galvanometer when a potential difference of $10 \mathrm{V}$ is maintained across AC.

Six similar bulbs are connected as shown in the figure with a DC source of emf $E$, and zero internal resistance.
The ratio of power consumption by the bulbs when $\left(\mathrm{i}\right)$ all are glowing and $\left(\mathrm{ii}\right)$ in the situation when two from section $A$ and one from section $B$ are glowing will be,