First, since we are in alternating current, the lightbulb is (or has) an impedance, which is:

Z = R +jX (I guess a light bulb is an ideal resistor in series with a very small coil)

I don't know if these 450 ohm refer to R or |Z|. That's the first question.

Second, if I divide 230V/450ohm I get that it needs 0.5A aprox. So, then, the power must be V•I, which is 230x0.5 = 115W. Second question, I don't know if these are the S 115VA, or the P 115W. Like in the power formula S [VA]= P [W] +jQ [VAr]

Third, that's a very high power for a little light bulb, so I checked the amperage with my multi, setting it in series with the light bulb. I read 0.045A, so it's actually 10W, which makes more sense.

So the third question is why am I getting theoretically 115W and in practice 10W.

Thank you