The energy stored in a 51.0 µF capacitor is used to melt a 4.00 mg sample of lead. To what voltage must the capacitor be initially charged, assuming that the initial temperature of the lead is 20.0°C? Lead has a specific heat of 128 J/kg°C, a melting point of 327.3°C, and a latent heat of fusion of 24.5 kJ/kg.
2007-02-08 14:18:41 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Ec=.5CV^2
Ec-energy stored in the capacitor
C – capacitance
V – potential difference (voltage applied)
Elead=mCp(T2-T1) + mCf
Elead – energy required to heat lead to reach a melting point and then to melt lead
Cp heat capacity of lead
Cf latent heat of fusion
T2 temperature of melting
T1 initial temperature
M mass of lead
Ec=Elead
V=sqrt(2 [m(Cp(T2-T1)+Cf)]/C)
V=sqrt(2[4e-3(128(327.3-20.0)+24.5)]/51.0e-6)
V=2,485V
2007-02-08 14:57:13 · answer #1 · answered by Edward 7 · 0⤊ 0⤋