An electric heater of resistance $8 \, \Omega$ draws $15 \, A$ from the service mains for $2$ hours. Calculate the rate at which heat is developed in the heater (in $W$).

What is meant by saying that the potential difference between two points is $1$ $V$?

$A$ hot plate of an electric oven connected to a $220\, V$ line has two resistance coils $A$ and $B$,each of $24\,\Omega$ resistance,which may be used separately,in series,or in parallel. What are the currents in the three cases?

The values of current $I$ flowing in a given resistor for the corresponding values of potential difference $V$ across the resistor are given below -

$I$ (amperes)	$0.5$	$1.0$	$2.0$	$3.0$	$4.0$
$V$ (volts)	$1.6$	$3.4$	$6.7$	$10.2$	$13.2$

Plot a graph between $V$ and $I$ and calculate the resistance of that resistor.

Several electric bulbs designed to be used on a $220\, V$ electric supply line,are rated $10\, W$. How many lamps can be connected in parallel with each other across the two wires of a $220\, V$ line if the maximum allowable current is $5\, A$?

Show how you would connect three resistors,each of resistance $6 \, \Omega$,so that the combination has a resistance of $(i)$ $9 \, \Omega$,$(ii)$ $4 \, \Omega$.