Question

To describe the phase relation between current and voltage, we use particular words: In the circuit represented by these phasors, the current the voltage, leads lags is perpendicular to is out of phase with The appropriate answer here is B although C and D are also correct. Explain what answer B means: A capacitor has a peak current of 330 mu A when the peak voltage at f = 250 kHz is 2.2 V. What is the capacitance C? If the peak voltage is held constant, what is the peak current at 500 kHz? Assume that we have a capacitor in series with a resistor. The loop law says that the voltage of the power source is distributed between the resistor and the capacitor. Since the reactance of the capacitor X_C depends on the frequency source, the capacitor voltage V_C and the resistor voltage V_g both depend on the frequency:

Answer 1

(35.4)solution as seen from the phasor diagram of current and voltages given if we observe carefully the reference axis is the X-axis the phases can be calculated in the first quadrant so the current lag behind the voltage so option (B) is correct although the the options (C) and (D) are correct means at a glance it self we can be sure that the angle difference between i andVis 90 soi and V are perpendicular to each other in the anti clockwise direction, the phase difference between i and Vis 360-90-270 out of phase so options (C) and (D) are corredt (35.5)solutiorn (a) given the peak current-i330HA. peak voltage,V-2.2V frequency-f-250KHz the rel ati on between the peak current and voltage and capacitance is peak current i-aCV 330x106 9.55x101p 2TV (2) (3.14) (250x10) (22) C 95.5p (b)if,f - 500KHz (2)(3.14) (500x10) (95.5x10(22)-660x10° A peak current i-660uA