$A$ battery of $9 \, V$ is connected in series with resistors of $0.2 \, \Omega$,$0.3 \, \Omega$,$0.4 \, \Omega$,$0.5 \, \Omega$,and $12 \, \Omega$ respectively. How much current (in $A$) would flow through the $12 \, \Omega$ resistor?

Draw a labelled circuit diagram showing three resistors $R_{1}, R_{2}$ and $R_{3}$ connected in series with a battery $(E)$,a rheostat $(Rh)$,a plug key $(K)$ and an ammeter $(A)$ using standard circuit symbols. Use this circuit to show that the same current flows through every part of the circuit. List two precautions you would observe while performing the experiment.

Five bulbs are connected in a series circuit. If the third bulb in the middle blows out,what happens?

$B_{1}$,$B_{2}$ and $B_{3}$ are three identical bulbs connected as shown in the figure. When all the three bulbs glow,a current of $3 \, A$ is recorded by the ammeter $A$.
$(i)$ What happens to the glow of the other two bulbs when the bulb $B_{1}$ gets fused?
$(ii)$ What happens to the reading of $A_{1}$,$A_{2}$,$A_{3}$ and $A$ when the bulb $B_{2}$ gets fused?

Derive the relation $R = R_{1} + R_{2} + R_{3}$ when three resistors $R_{1}, R_{2}$ and $R_{3}$ are connected in series in an electric circuit.

Calculate the equivalent resistance between the points $A$ and $B$ in the following combination.