$A$ hot plate of an electric oven connected to a $220 \ V$ line has two resistors $A$ and $B$ each of $22 \ \Omega$ resistance. These resistors may be used separately,in series,or in parallel. Find the current flowing in all the three cases.

An electric geyser is connected to a $220 \; V$ line and consumes $4.4 \; kWh$ of electrical energy in $1 \; hour$. What is the resistance of the geyser?

The quantity of charge flowing past a point multiplied by time is current.

Three $2 \,\Omega$ resistors,$A, B$ and $C,$ are connected as shown in the figure. Each of them dissipates energy and can withstand a maximum power of $18 \,W$ without melting. Find the maximum current $I$ that can flow through the circuit.

$(a)$ Name an instrument that measures electric current in a circuit. Define the unit of electric current.
$(b)$ What do the following symbols mean in circuit diagrams?
$(c)$ An electric circuit consisting of a $0.5 \ m$ long nichrome wire $XY$,an ammeter,a voltmeter,four cells of $1.5 \ V$ each and a plug key was set up.
$(i)$ Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points $X$ and $Y$ and the electric current flowing through $XY$.
$(ii)$ The following graph was plotted between $V$ and $I$ values. What would be the values of $V/I$ ratios when the potential difference is $0.8 \ V$,$1.2 \ V$ and $1.6 \ V$ respectively? What conclusion do you draw from these values?

$A$ bulb gets dimmer for a moment when a geyser,connected across the same source,is switched on. Why?