An iron nut of mass 50 g is heated from room temperature to its melting point in 52 s through magnetic induction as shown in Figure P22.85. The circuit has a capacitance of 560 nF so that it will operate at its resonant frequency of 173 kHz with an input rms voltage of 1000 V.
(a) If this inductive heater is 90% efficient, what is the power supplied to the inductor of this circuit to heat the iron? The melting temperature of iron is 1810 K, and its specific heat is 440 J/(kg K).
(b) What is the inductance of the coil of thick copper wire?
(c) What is the rms current through the coil? Is the thick copper wire needed?
(d) The needed capacitance is provided by placing 12 identical capacitors in parallel. What is the capacitance of one of these capacitors? 

Transcribed Image Text:

Figure P22.85