How is alternating current $(AC)$ different from direct current $(DC)$?

Draw a circuit diagram for a circuit consisting of a battery of five cells of $2 \text{ V}$ each, a $5 \, \Omega$ resistor, a $10 \, \Omega$ resistor, and a $15 \, \Omega$ resistor, an ammeter, and a plug key; all connected in series. Also, connect a voltmeter to record the potential difference across the $15 \, \Omega$ resistor and calculate:
$(i)$ the electric current passing through the above circuit and
$(ii)$ the potential difference across the $5 \, \Omega$ resistor when the key is closed.

$(a)$ Explain the difference between direct current and alternating current. Write one important advantage of using alternating current.
$(b)$ An air conditioner of $2 \,kW$ is used in an electric circuit having a fuse of $10 \,A$ rating. If the potential difference of the supply is $220 \,V$,will the fuse be able to withstand the current when the air conditioner is switched on? Justify your answer.

Which of the following is the symbol for a resistor?

Draw a circuit diagram of an electric circuit containing a cell,a key,an ammeter,a resistor of $2\,\Omega$ in series with a combination of two resistors ($4\,\Omega$ each) in parallel and a voltmeter across the parallel combination. Will the potential difference across the $2\,\Omega$ resistor be the same as that across the parallel combination of $4\,\Omega$ resistors? Give reason.

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.