Bộ tài liệu bài tập tham khảo môn vật lý bậc đại học bằng tiếng anh Chapter 31 | V. V V a V. f t -V2 V2 b Since the voltage is sinusoidal the average is zero. a I 42Ims 72 A A. b Irav jI j A A. c The root-mean-square voltage is always greater than the rectified average because squaring the current before averaging then square-rooting to get the root-mean-square value will always give a larger value than just averaging. V V 3L3 a V Ki IwL 1 - 100 rad s H 0-120A b I - . rnL 1000 rad s H c I - 60 . rnL 10 000 rad s H Log w a V IXC I VmC V 100 rad s X 10- 6 F A. C mC b I VmC V 10000 rad s X 10-6 F A. c I VmC V 10 000 rad s X 10-6F A. d A . .. . .. . Los 1 . .Ị. .. . .. 100 200 500 1000 2000 5000 10000 Log u a XL mL 2nfL 2n 80 Hz H 1508 Q. b XL mL 2f L -L 120 Q s H. L 2nf 2n 80 Hz c XC 4r 1 _ 497 Q. C ữC 2f 2 80 Hz X 10 F d XC 4r C -4- 1_ X 10-5 F. C 2rfC 2rfXc 2 80 Hz 120 Q a XL mL 2nfL 2n 60 Hz H 170Q. If f 600 Hz XL 1700Q. b Xr -4 4- 4 _ 1061 Q. If f 600 Hz Xr C mC 2nfC 2 60 Hz X10-6 F C Q . c XC XL mL m 1 . 1 943 rad s mC y LC ự H X 10 6 Hz so f 150 Hz. VC - C -î mC mVC A 2n 60 Hz 170 V X 10-5 F. VL loL f -V ------------- 12-OV ------------ x 1q6 Hz. L 2nIL 2n x 10 A x 10 4 H v V cos 720 rad s t a i A cos 720 rad s t . R 150 Q b XL oL 720 rad s H 180 Q. c vL L - oL A sin 720 rad s t - V sin 720 rad s t . dt oC 120 rad s x 10-6 F 1736 Q. b To find the voltage across the resistor we need to know the current which can be found from the capacitor remembering that it is out of phase by 90o from the capacitor s voltage . vc i C Xc Xc 1736 Q vR iR x 10-3 A 250 Q cos 120 rad s t V cos 120 rad s t . a Xc vcos cos 120rad s t x w-3 a 120 rad s a If o o - X oL - X - -----
