What is the unit of resistance?

$(a)$ 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 $xZy$.

What is the $SI$ unit of electric potential?

$V-I$ graphs for two wires $A$ and $B$ are shown in the figure. If both the wires are made of the same material and are of equal thickness,which of the two is of more length? Give justification for your answer.

$(a)$ Name the effect of electric current which is utilised in the working of an electrical fuse.
$(b)$ How is a fuse connected in a domestic circuit?

There are two electric bulbs,$(i)$ marked $60\, W, 220\, V$ and $(ii)$ marked $100\, W, 220\, V$. Which one of them has higher resistance?