$A$ cell,a resistor,a key and an ammeter are arranged as shown in the circuit diagrams of the figure. The current recorded in the ammeter will be

Explain the following.
$(a)$ Why is the series arrangement not used for domestic circuits?
$(b)$ How does the resistance of a wire vary with its area of cross-section?

How would the reading of the voltmeter $(V)$ change if it is connected between points $B$ and $C$? Justify your answer.

$(a)$ Derive an expression to find the equivalent resistance of three resistors connected in series. Also,draw the schematic diagram of the circuit.
$(b)$ Find the equivalent resistance of the following circuit.

$(a)$ Explain how a cell maintains current in a circuit.
$(b)$ In the circuit given below,the resistance of the path $xTy = 2 \, \Omega$ and that of $xZy = 6 \, \Omega$.
$(i)$ Find the equivalent resistance between $x$ and $y$.
$(ii)$ Find the current in the main circuit.
$(iii)$ Calculate the current that flows through the path $xTy$ and $xZy$.

$(a)$ Calculate the resistance of the wire using the graph.
$(b)$ How many $176 \,\Omega$ resistors in parallel are required to carry $5\, A$ on a $220\, V$ line?
$(c)$ Define electric power. Derive the relation between power,potential difference,and resistance.