The equivalent resistance in series combination is

Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of $1.5\, V$,$5\, \Omega$,$10\, \Omega$ and $15\, \Omega$ resistors and a plug key,all connected in series.

If resistors are connected in parallel,the voltage across each remains the same.

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.

Derive an expression for equivalent resistance when three resistors of resistance $R_{1}, R_{2}$ and $R_{3}$ are connected in parallel.

$A$ heater is joined in parallel with a $60\, W$ bulb and connected to the mains. If the $60\, W$ bulb is replaced by a $100\, W$ bulb,will the rate of heat produced by the heater be more,less,or remain the same?