Question

The parallel plates in a capacitor, with a plate area of 9.00 cm2 and an air-filled separation of 3.30 mm, are charged by a 5.40 V battery. They are then disconnected from the battery and pulled apart (without discharge) to a separation of 8.10 mm. Neglecting fringing, find (a) the potential difference between the plates, (b) the initial stored energy, (c) the final stored energy, and (d) the work required to separate the plates

Answer 1

2 Here are a (A) - 9.0 gem? ax(100) m2 - 4 A 2 qx 10 to A di. As air filled] ore, d, = 3.3 mm = 3.3X163 mi power supply (N) = 5.40 now, chart capacitor (e) [As CS (8.854x90+') x 9*10! 3.3% 10-3 = P2415 x10-12 Fi Charge 3 = C,V, - (2.415X10/2)x gode e; e now, when, seperation is(da) = 8.1 mm -8.1X10-2m; Capacitance (02) tot (8.854x1012) x 9x109 = 1:30 41 X10 11 2 dz 8.1.8103 F 9.838x10 13 mors, as, 29 = C, V. [Voz potn diff bek" plates Oro, V2 = 1.30410161 C2 V 13.3 Volt 9.838 x 10-13 :(a) the poth diff beth the plates is (13.3 Volt The initial stored energy is, (B) = CiviPex 12:415x10'3) x(5.4)'J = 3.58 x10" . Initial stored energy is 13.52 x 10
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(2 The final stored energy is (Ef) 2 + 2 C2 V 22 On, Eg(9.838x10 '3) * * (1313) = 8.70x10-11] final stored is 18.70 X10 3 energy & the work required to seperate the plates is, W = Ef - € ;-) (8.70x10") – (3.52x10')]; -11 = 5:18 X10 J ... The work required to seperate the plates is, 5-18 x 10-11|1]
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