How are ammeters and voltmeters connected in a circuit? What do they help us measure?

$(a)$ $(i)$ What is meant by saying that the potential difference between two points is $1 \, V$? $(ii)$ How much energy is given to $5 \, C$ of charge passing through a $12 \, V$ battery? $(b)$ Describe an activity with a necessary electric circuit to study the factors on which the resistance of a conducting wire depends.

Compare the power used in the $2 \,\Omega$ resistor in each of the following circuits: $(i)$ a $6 \,V$ battery in series with $1 \,\Omega$ and $2 \,\Omega$ resistors,and $(ii)$ a $4 \,V$ battery in parallel with $12 \,\Omega$ and $2 \,\Omega$ resistors.

Two electric lamps of $100\, W$ and $25\, W$ respectively are joined in parallel to a supply of $200\, V$. Calculate the total current flowing through the circuit. (in $, A$)

An electric bulb rated $220 \, V, 60 \, W$ is working at full efficiency. $(i)$ State the resistance of the coil of the bulb. Another identical bulb is connected in series with the first one and the system is connected across the mains as shown below. $(ii)$ State the rate of conversion of energy in each bulb. $(iii)$ Calculate the total power. $(iv)$ What will be the total power if the bulbs are connected in parallel?

In the given circuit,calculate $(i)$ total resistance of the circuit,and (ii) current shown by the ammeter.