n00b

Thanks for all your answers (even though they're all way over my head). Um, actually the K I was referring to in the original post was the equilibrium constant as per: According to Wikipedia: However, in our high school Chemistry class we were told explicitly that, although pressure and volume could effect the position of equilibrium (shift it left or right), only changes in pressure would effect K. This is the bit I don't understand, as per my original post. Sorry for being daft if all your answers above did actually answer my question.

I know that temperature is the only factor that changes K (the equilibrium constant). What I want to know is, why don't pressure and volume affect K? Say, for example, that an increase in pressure moves equilibrium to the right. Wouldn't this then increase the concentration of products, reduce concentration of reactants and therefore increase K?

Light is part of the electromagnetic spectrum. Photons can excite photovoltaic cells to produce electricity. Can photons produce a measurable magnetic field?

If light is part of the electromagnetic spectrum, does this mean that light can be influenced by strong magnetic fields?

I know the speed of electromagnetic radiation in a vacuum is roughly 300,000 metres per second. I was wondering if anyone knows how fast the speed of electricity is as it moves through a household circuit? Presumably resistance of the copper wires would slow it down, but to what value?