Who invented the simple battery?

If the work done to take $3 \,C$ electric charge from one point to another point is $15 \,J$,what will be the potential difference between these two points (in $,V$)?

The $V-I$ graphs for two wires $A$ and $B$ are shown in the figure. If we connect both the wires one by one to the same battery, which of the two will produce more heat per unit time? Give justification for your answer.

$(a)$ What is an electric circuit?
$(b)$ Calculate the number of electrons that flow per second to constitute a current of one ampere. The charge on an electron is $1.6 \times 10^{-19} \ C$.
$(c)$ Draw an electric circuit for studying Ohm's law. Label the circuit components used to measure electric current and potential difference.

If the charge on an electron is $1.6 \times 10^{-19} \text{ C}$,find the approximate number of electrons in $1 \text{ C}$.

What will happen to the current flowing through a conductor,if the potential difference is doubled?