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HOMEWORK 11 1- In an oscillating LC circuit, L=5.0 mH and C=2.0 µF. At t=0 the charge in the capacitor is zero and the current is 2.0 A. (a) What is the maximum charge that will appear in the capacitor? (b) At what earliest time t>0 is the energy stored in the capacitor greatest and what is that greatest energy? (c) What is the current in the circuit at that time? (d) What is the frequency of the oscillatory charge? 2- A series RLC circuit has inductance L=10 mH, capacitance C=1.6 µF and resistance R=1.5 Ω. (a) What is the frequency of oscillation of the current? (b) What is the charge on the capacitor after 50 cycles? (c) Find the time required for the maximum energy stored in the capacitor during one oscillation to fall to half its initial value. 3- A 10 mH inductor is connected to an ac generator with emf 30V cos(300 s-1 t). (a) What is the maximum value of the current? (b) When the current is a maximum, what is the emf of the generator? (c) When the emf is 12V and increasing in magnitude, what is the current? 4- A 2.0 µF capacitor is connected to the same emf of problem 3. (a) What is the amplitude of the resulting alternating current? (b) What is the maximum charge on the capacitor? 5- The generator of problem 3 is connected in series to a RLC circuit having inductance L=10 mH, capacitance C=1.6 µF and resistance R=1.5 Ω. Find (a) the capacitive reactance XC, (b) the impedance Z, and (c) the current amplitude I. A second capacitor of identical capacitance is then connected in series with the other components. Determine whether the values of XC, Z or I will increase, decrease or remain unchanged. 6- A transformer has 60 primary turns and 500 secondary turns. If VP is 120 V, what is the secondary voltage?