What makes the electric current flow through an electrolyte?

List in a tabular form two differences between a voltmeter and an ammeter.

Sonika is working with the circuit shown in the figure. There are two open terminals in the circuit: $X$ and $Y$. She has wires made of five different materials: $I, II, III, IV,$ and $V$. She knows that the electric bulb will glow only when wires made of conducting materials are connected across both open terminals. She records her observations in a table. After the experiment,ink spills on the paper,and she loses the information for the third row.

$S.No.$	Material at $X$	Material at $Y$	Electric Bulb ($ON$/$OFF$)
$1$	$I$	$II$	$OFF$
$2$	$I$	$IV$	$ON$
$3$	-	-	$OFF$
$4$	$III$	$V$	$ON$

Based on the remaining information in the table,which materials could be in the third row?

How many electrons will there be in $1.6 \ C$ charge?

Out of the following bulbs rated $40 \ W, 220 \ V$,$60 \ W, 220 \ V$,and $100 \ W, 220 \ V$,which one will glow the brightest when connected in series to a supply of $220 \ V$?

Which law is used to calculate the magnitude of the electric force between two electric charges?