What does the labelling of a conductor such as: 24 W 12 V mean? Does this mean the resistance of the wire or the current?

Question

So I came across a question where a lamp was labelled 24 W and 12 V. 2 lamps that were identical and had this labelling were then put in series with a voltage supply of 12 V.
Obviously the individual voltage going through the lamps are 6V. But what I don't understand is that when there is this labelling of 24 W and 12 V, does this mean that the lamps will consume a current of 2A or does this mean the resistance will be 6 ohms (as P=IV and P=V^2/R)?
I personally don't think it will be trying to label the resistance of the lamp especially because resistance depends on the temperature of the wires...
Thanks for any help!

David White · Accepted Answer

24W is the power consumption of each lamp when connected across a 12V source.  Also note that when two of these lamps are connected in series across a 12V source, each lamp is experiencing a 6 volt DROP (it's not entirely correct to say that 6 V are going through each lamp).
With the given information, you can easily calculate the resistance of each lamp.  There are three general formulas that are used to calculate power consumption, and the one that applies here is:
$P=V^2/R$
This can be algebraically rearranged to calculate resistance.
$R=V^2/P$
Using the stated numbers, this gives a resistance of 6 ohms.

What does the labelling of a conductor such as: 24 W 12 V mean? Does this mean the resistance of the wire or the current?

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