In Fig. 31-35, let the rectangular box on the left represent the (high-impedance) output of an audio amplifier, with r = 1000 Ω. Let R = 10 Ω represent the (low-impedance) coil of a loudspeaker. For maximum transfer of energy to the load R we must have R = r , and that is not true in this case. However, a transformer can be used to “transform" resistances, making them behave electrically as if they were larger or smaller than they actually are. (a) Sketch the primary and secondary coils of a transformer that can be introduced between the amplifier and the speaker in Fig. 31-35 to match the impedances. (b) What must be the turns ratio?
In Fig. 31-35, let the rectangular box on the left represent the (high-impedance) output of an audio amplifier, with r = 1000 Ω. Let R = 10 Ω represent the (low-impedance) coil of a loudspeaker. For maximum transfer of energy to the load R we must have R = r , and that is not true in this case. However, a transformer can be used to “transform" resistances, making them behave electrically as if they were larger or smaller than they actually are. (a) Sketch the primary and secondary coils of a transformer that can be introduced between the amplifier and the speaker in Fig. 31-35 to match the impedances. (b) What must be the turns ratio?
In Fig. 31-35, let the rectangular box on the left represent the (high-impedance) output of an audio amplifier, with r = 1000 Ω. Let R = 10 Ω represent the (low-impedance) coil of a loudspeaker. For maximum transfer of energy to the load R we must have R =r, and that is not true in this case. However, a transformer can be used to “transform" resistances, making them behave electrically as if they were larger or smaller than they actually are. (a) Sketch the primary and secondary coils of a transformer that can be introduced between the amplifier and the speaker in Fig. 31-35 to match the impedances. (b) What must be the turns ratio?
In an oscillating LC circuit with L = 44 mH and C = 4.9 μF, the current is initially a maximum. How long will it take before the capacitor is fully charged for the first time?
At a given time t in an LC circuit, the energy in the capacitor is 25.0% of the energy in the inductor. For this condition to occur, what fraction of a period must elapse following the time the capacitor is fully charged (at t=0)?
A. 0.217
B. 0.152
C. 0.167
D. 0.176
In an oscillating LC circuit, L = 3.00 mH and C = 2.70 mF. At t = 0 the charge on the capacitor is zero and the current is 2.00 A. (a) What is the maximum charge that will appear on the capacitor? (b) At what earliest time t > 0 is the rate at which energy is stored in the capacitor greatest, and (c) what is that greatest rate?
University Physics with Modern Physics (14th Edition)
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