Philip M It might be considered unconventional, but in the second line of the solution, the 'u' (mu) substitutes adequately for the 10^-6. Their answer is correct. Paul D ----- Original Message ---- From: philip madsen <pma15027@xxxxxxxxxxxxxx> To: geocentrism@xxxxxxxxxxxxx Sent: Wednesday, 26 September, 2007 5:04:18 AM Subject: [geocentrism] modern edu Please tell me I aint nuts. I don't use formula often, so though I instinctively say reactance is I forget the application for microfarads when the unit is Farad in this equation. Yet just look how this formula is applied in not one but two different websites.. . Note they correctly state for this formula, C is capacitance in farads yet substitute microfarads into the equation. Isn't their answer wrong. shouldn't there be a 10^6 on the top line. 50 micro Farads = 50 x 10 to the -6th. Farads. Or am I just too old and missing something. Can a math man please check me out? I compute the answer should be 31,250 ohms. Philip. Quote, Now you can understand why it is said that the XC varies inversely with the product of the frequency and capacitance. The formula is: Where: XC is capacitive reactance in ohms, f is frequency in Hertz, C is capacitance in farads, p is 6.28 (2 X 3.1416) The following example problem illustrates the computation of X C. Sick of deleting your inbox? Yahoo!7 Mail has free unlimited storage. http://au.docs.yahoo.com/mail/unlimitedstorage.html