Lösning 4.4:10
FörberedandeFysik
\displaystyle U = 230 V \displaystyle P = 500 W \displaystyle R = 17,1 \Omega
\displaystyle P = UI\cdot \cos\phi \displaystyle \cos\phi = U_R/U_Z = RI /ZI = R/Z
\displaystyle \omega = 314 rad/s
\displaystyle U = I\cdot Z \displaystyle P=UI\cdot R/Z = U^2R/Z^2
\displaystyle 500 = 230^2 \cdot 17,1/Z^2
\displaystyle Z = 42,5 \Omega \displaystyle \cos\phi = 17,1/42,5 = 0,40
\displaystyle Z = \sqrt{R^2 + \omega ^2 L^2} \displaystyle 42,5 = \sqrt{17,1^2 + 314^2L^2}
\displaystyle L = 0,123 H