Passage VII

An RCL circuit contains an alternating current (AC) power supply, a resistor having a resistance R, a capacitor having a capacitance C, and an inductor having an induc­tance L (see Figure 1).

The capacitor and inductor each possess impedance, a type of electrical resistance. The angular frequency of the cur­rent, ω, is a measure of the number of times each second that the current reverses direction.

Figure 2 shows, for specific values of C, L, and average voltage, V, how the average current, I, varies with ω and with R.

Figure 2 adapted from David Halliday and Robert Resnick, Physics, Part 2, 3rd ed. ©1978 by John Wiley and Sons, Inc.

For a given R, the peak average current, Imax, occurs at the resonant angular frequency, ω0 .

Figure 3 shows how ω0 varies with L and C.

40. For a given L, what is the correct ranking of the values of C in Figure 3, from the C associated with the lowest ω0 to the C associated with the highest ω0 ？

Answer and Explanation

Your Answer is

Correct Answer is J

Explanation

Arbitrarily take an abscissa in figure 3, and compare the ordinates corresponding to different Cs.

For example, take the abscissa as 1.0, C=1.0×10-10 is the smallest, but the corresponding ω0 is the largest;

C=3.0×10-10 is the largest, but the corresponding ω0 is the smallest