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Monday, November 12, 2012

Answer to capacitor question

(a)
V across 200k resistor = IR
V= (2x105) (2x 10-5) = 4V
VC = E - VR = 6-4 = 2V
(b)
Q=VC
Q = (2.0) (560 x 10-6) = 1.12 x 10-3 C
 
(c)
W = ½ CV2
W = ½ (560 x10-6) (2)2 = 1.12 x 10-3 J
 
(d)
 W = Emf x charge
W = 6V x 1.12 x 10-3 C = 6.72 x 10-3 J
 
(e) Work is done transferring the charge through the external resistance. This is transferred to heat energy in the resistor