Three $V -I$ graphs are drawn individually for two resistors and their series combination. Out of $A, B,C$ which one represents the graph for series combination of the other two. Give reason for your answer.
$(a)$ Nichrome wire of length $L^{\prime}$ and radius ${ }^{\prime} R^{\prime}$ has resistance of $10\, \Omega$. How would the resistance of the wire change when
$(i)$ only length of the wire is doubled ?
$(ii)$ only diameter of the wire is doubled ? Justify your answer.
$(b)$ Why element of electrical heating devices are made$-$up of alloys ?
Two wires $A$ and $B$ are of same metal, have the same area of cross$-$section and have their lengths in the ratio $2: 1$. What will be the ratio of currents flowing through them respectively, when the same potential difference is applied across length of each of them ?
The formula for an electric current is $.....$
An electric heater consumes $1.1 \,kW$ power when $220\, V$ voltage is applied to it. How much current will be flowing through it?