Mention one reason why tungsten is used for making the filament of an electric lamp.

What is the other name of the commercial unit of electrical energy?

What will happen to the current flowing through a conductor,if the potential difference is doubled?

$A$ cell,a resistor,a key and an ammeter are arranged as shown in the circuit diagrams of the figure. The current recorded in the ammeter will be

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.

$(a)$ Calculate the resistance of the wire using the graph.
$(b)$ How many $176 \,\Omega$ resistors in parallel are required to carry $5\, A$ on a $220\, V$ line?
$(c)$ Define electric power. Derive the relation between power,potential difference,and resistance.