An electric iron consumes energy at a rate of $840\, W$ when heating is at the maximum rate and $360\, W$ when the heating is at the minimum. The voltage is $220\, V$. What are the current and the resistance in each case?

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?

Two lamps,one rated $100 \, W$ at $220 \, V$ and the other $60 \, W$ at $220 \, V$,are connected in parallel to a $220 \, V$ supply. Find the current drawn from the supply line.

No current flows between two charged bodies when connected,if they have the same

Derive the relation $R = R_{1} + R_{2} + R_{3}$ when three resistors $R_{1}, R_{2}$ and $R_{3}$ are connected in series in an electric circuit.

Three resistors of $5 \, \Omega$,$10 \, \Omega$,and $15 \, \Omega$ are connected in series,and the combination is connected to a battery of $30 \, V$. An ammeter and a voltmeter are connected in the circuit. Draw a circuit diagram to connect all the devices in the correct order. What is the current flowing through the circuit and the potential difference across the $10 \, \Omega$ resistor?