Bộ tài liệu bài tập tham khảo môn vật lý bậc đại học bằng tiếng anh Chapter 24 | Q CV pF x 10 4 C. a A m2 C 0 0----------- pF. 0 d 0 m b c a b c TZ Q x 10 8 C V ----------- C 10 F kV. E V x 103V x 106 v in. d m __ Q x 10 V ---------- C x 10 6 c 604 V. 40 f A Cd 2-45 x 10 10f 0-328 x 10 m 0 0091 m2 0 E ------604 V x 106 Vm. d x 10 3 m 0 d E o 0E 0 x106 Vm x 10 5 C m2. 0 AV Ed d _ x 10 C m2 m x 10 C2 Nm2 mV a Q CV 120 C b C 0 A d d d 2 means C C2 and Q Q 2 60 pC c r 2r means A 4A C 4C and Q 4Q 480 pC a V since the plates remain charged. b i V Q Q does not change since the plates are disconnected from the battery. C A d If d is doubled C 2 C so V 2V V ii A nr2 so if r 2r then A 4A and C 4C which means that V 1V V 4 Estimate r cm s0 A s0nr2 s0n m 2 C so d -2------- -----------A- d C x 10 2 F The separation between the pennies is nearly a factor of 10 smaller than the diameter of a penny so it is a reasonable approximation to treat them as infinite sheets. a AV Ed 100 V 104N C d d 10 2 m cm C 0A - E R d d R Cd 4Cd y ns0 y 4ne0 R J4 x 10F 10 2m 9 x 109 m V C2 R x 10 2 m cm b Q CV 5pF 100 V 500 pC C _ 2ne0 L n rb ra C 0J80m 2ne0 x 10-12-F ln b V Q C x 10-12C x 10-12 F V a C 2ne0 . 2ne0 T y f a 7 Y L n rb ra CL Q C b Q V- L L ------2n 1-77 5-84. x 10 Fm ra x 10 F m x 10 Cm. 2np 2np a CL ---------- ----------------0--------- x 10 F m. ln rb ra ln mm mm b The charge on each conductor is equal but opposite. Since the inner conductor is at a higher potential it is positively charged and the magnitude is Q CV -L m l .35 x 10-11C. ln rb ra ln mm mm a For two concentric spherical shells the capacitance is C f rab kCrb - kCra rarb rb kCra b a a b b k I rb-ra J kC-ra _ k 116 x 10-12 F m n rb m. b k 116 x 10 F m b V 220
