Define an electric circuit. Distinguish between an open and a closed circuit.

An electric bulb should be connected to how much voltage line if it draws an electric current of $0.5\, A$,the resistance of the filament of that bulb being $440\, \Omega$ (in $, V$)?

Which of the following is true for a parallel combination of two resistors?

An electric bulb works on the heating effect of current.

$(a)$ State the commercial unit of electric energy and find its relation with its $SI$ unit.
$(b)$ The current through a resistor is made three times its initial value. Calculate how it will affect the heat produced in the resistor.
$(c)$ Find the increase in the amount of heat generated in a conductor if another conductor of double resistance is connected in the circuit,keeping all other factors unchanged.

State with the help of a circuit diagram an activity to find the resistance $R$ of a given wire. $A$ current of $0.2 \, A$ passes through a resistor of $20 \, \Omega$. Find the potential difference across its ends.