In an experimental set-up as shown below,a piece of silver was placed touching points $A$ and $B$. Next time it was replaced by a piece of wood. In which case did the bulb glow? Give reason to justify the observation.

In the circuit shown below, calculate:
$(a)$ total resistance in arm $CE$,
$(b)$ total current drawn from the battery, and
$(c)$ current in each arm, i.e., $AB$ and $CE$ of the circuit.

Which of the following combinations of cells in series (as shown in the figure) correctly represents the arrangement to obtain maximum potential?

$(a)$ In the circuit shown, connect a nichrome wire of length $L$ between points $X$ and $Y$ and note the ammeter reading.
$(i)$ When this experiment is repeated by inserting another nichrome wire of the same thickness but twice the length $(2L)$, what changes are observed in the ammeter reading?
$(ii)$ State the changes that are observed in the ammeter reading if we double the area of cross-section without changing the length in the above experiment. Justify your answer in both cases.
$(b)$ "Potential difference between points $A$ and $B$ in an electric field is $1\, V$." Explain the statement.

If the cross-sectional area of a conducting wire is doubled,what will be the effect on its resistance?

An electric heater consumes $1.1 \,kW$ power when $220 \,V$ voltage is applied to it. How much current will be flowing through it (in $,A$)?