What is the formula to find electric power $P$?

Why is parallel arrangement used in domestic wiring?

How many microamperes $(\mu A)$ are equal to $1$ milliampere $(mA)$?

$B_{1}$,$B_{2}$ and $B_{3}$ are three identical bulbs connected as shown in the figure. When all the three bulbs glow,a current of $3 \, A$ is recorded by the ammeter $A$.
$(i)$ What happens to the glow of the other two bulbs when the bulb $B_{1}$ gets fused?
$(ii)$ What happens to the reading of $A_{1}$,$A_{2}$,$A_{3}$ and $A$ when the bulb $B_{2}$ gets fused?

What is the resistance of an ideal voltmeter?

An electric bulb works on the heating effect of current.