Voltage across components in a series circuit

We measure in a circuit with a .

The voltmeter is connected in with the component.

Circuit with a cell, switch and lamp connected in series, and a voltmeter connected across the lamp.

The supply voltage is shared between components in a series circuit, so the sum of the voltages across all of the components in a series circuit is equal to the supply voltage, \({V_s}\).

Circuit with a battery, closed switch and three lamps connected in series. A voltmeter across the battery is labelled 'Vs = 12 V'; a voltmeter connected across the first lamp is labelled 'V1 = 4 V'; a voltmeter connected across the second lamp is labelled 'V2 = 4 V'; and a voltmeter connected across the third lamp is labelled 'V3 = 4 V'. — Figure caption,
Circuit with a cell, closed switch and three lamps connected in a series

We can write this voltage relationship as:

\({V_s} = {V_1} + {V_2} + {V_3} + ....\)

The voltage across each of the components in series is in the same proportion as their :

if two identical components are connected in series, the supply voltage divides equally across them
if one component has twice as much resistance as the other, the voltage across the higher resistance component is double the voltage across the lower resistance component

Question

Look at the parallel circuit below - what are the voltmeter readings at each position when the switch is closed?

Position 1: 0 V, 3V or 6 V

Position 2: 0 V, 3V or 6 V

Position 3: 0 V, 3V or 6 V

Circuit containing a switch, 6V battery and two 100 ohm resistors in series. Label 1 points to a voltmeter connected across the battery, marked Vs. Labels 2 and 3 point to voltmeters connected across each resistor, marked V1 and V2 respectively. — Figure caption,
Series circuit

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Practical electrical and electronic circuitsVoltage across components in a series circuit