A child has drawn the electric circuit to study Ohm’s law as shown in Figure. His teacher told that the circuit diagram needs correction. Study the circuit diagram and redraw it after making all corrections.

$(a)$ What is the total resistance of $n$ resistors each of resistance ' $R^{\prime}$ connected in

$(i)$ series ?

$(ii)$ parallel ?

$(b)$ Calculate the resultant resistance of $3$ resistors $3\, \Omega, 4\, \Omega$ and $12\, \Omega$ connected in parallel.

Draw a schematic diagram of an electric circuit. (in the "on" position) consisting of a battery of five cells of $2\, V$ each, a $5\, \Omega$ resistor, a $8\, \Omega$ resistor, a $12$ $\Omega$ resistor and a plug key, all connected in series. An ammeter is put in the circuit to measure the electric current through the resistors and a voltmeter is connected so as to measure the potential difference across the $12\, \Omega$ resistor.

Calculate the reading shown by the

$(a)$ ammeter $(b)$ voltmeter in the below electric circuit

From the listed electrical devices, which releases heat energy that is not appreciated?

Define current. Give its $SI$ unit.

In Volta's cell, what is the direction of the flow of electrons?