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yjk91
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Homework Statement
A cube of gold (resistivity ?R = 2.44 10-8 O m, density ?D = 1.93 104 kg / m3, and specific heat c = 129 J / kg °C) that is 3.5 mm on a side is connected across the terminals of a 40-µF capacitor that initially has a potential difference of 340.0 V between its plates.
http://www.webassign.net/bauerphys1/26-p-052.gif
(b) When the capacitor is fully discharged, what is the temperature of the gold cube? (Use 20°C for room temperature.
The Attempt at a Solution
i found R = p L /A
and got 0.69714 * 10^-5 ohm
Q = C *V = 40 *10^-6 * 340 V = 136 * 10^-4 C
I = V/R = 340 / (0.69714 * 10^-5) = 487.7066 * 10^5 A
time t = Q/I = 136*10^-4 / (487.706*10^5) = 0.27885 * 10^-9s
E = V^2t/R = 340^2(0.27885*10e-9) / 0.69714e-5
= 4.6239 J
m = density * volume = 1.93 * 10e4 * 3.5*e-3^3 =82.74875e-5 kg
E = mc delta T
T = E/(mc) = 4.6239 / (82.74875e-5*129) = 43
Tf = 43+20= 63mm where did i go wrong?