An electric heater rated $1200 \ W$ operates $2 \ h$ per day. Find the cost of the energy required to operate it for $30$ days at ₹ $5.00$ per unit.

$A$ nichrome wire has a resistance of $10\, \Omega$. Find the resistance of another nichrome wire,whose length is three times and area of cross-section four times the first wire.

In a household,$5$ tube lights of $40 \text{ W}$ each are used for $5 \text{ hours}$ and an electric press of $500 \text{ W}$ for $4 \text{ hours}$ everyday. Calculate the total energy consumed by the tube lights and press in a month of $30 \text{ days}$.

The table given below provides the resistivity of three samples in $\Omega \cdot m$:

Sample	Resistivity $(\Omega \cdot m)$
$A$	$1.6 \times 10^{-8}$
$B$	$7.5 \times 10^{17}$
$C$	$44 \times 10^{-6}$

$(a)$ Which of them is a good conductor? Which is an insulator? Why?
$(b)$ $A$ wire of resistance $4 \ \Omega$ is folded on itself to double its thickness. Calculate the new resistance of the wire.

$1 \; kWh = \ldots \ldots \ldots \; \text{watt-seconds}$

Given below is a circuit showing current flowing in it. Identify each component $A, B, C, D$ of this circuit.