The equivalent resistance between points $A$ and $B$ of the following electric circuit will be $.........$

Tungsten is used almost exclusively for filaments of electric bulbs. List two reasons.

Find the equivalent resistance across the two ends $A$ and $B$ of this circuit.

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.

$(a)$ Name an instrument that measures electric current in a circuit. Define the unit of electric current.
$(b)$ What do the following symbols mean in an electric circuit?
$(c)$ Draw a closed circuit diagram consisting of a $0.5\, m$ long nichrome wire $XY$,an ammeter,a voltmeter,four cells of $1.5\, V$ each,and a plug key.

What is the electric charge passing through a cross-sectional area of the conductor per unit time called?