How can we measure the current in a circuit?

What is the $SI$ unit of electric charge?

State $Ohm's$ law. Write the mathematical representation of $Ohm's$ law. Use this relationship to define $1\, ohm.$ List two disadvantages of connecting different electrical appliances in series.

$(a)$ How is the direction of electric current related to the direction of flow of electrons in a wire?
$(b)$ Calculate the current in a circuit,if $500 \, C$ of charge passes through it in $10$ minutes.

$(a)$ What do the following symbols represent in a circuit? Write the name and one function of each.
$(b)$ Draw a schematic diagram of a circuit consisting of a battery of $12 \, V$,three resistors of $5 \, \Omega$,$10 \, \Omega$,and $20 \, \Omega$ connected in parallel,an ammeter to measure the total current through the circuit,and a voltmeter to measure the potential difference across the combination of resistors.
$(c)$ State any one advantage of connecting electrical devices in parallel with the mains instead of connecting them in series in a household circuit.

If a current of $0.5\;A$ is passed through an electric bulb for $1\;hour$, how much electric charge will pass through the bulb (in $C$)?