Learning goal: to analyze and design a passive, first-order low-pass filter using a series rl circuit. the analysis and design will be repeated for a series rc circuit. an electrocardiogram needs to detect periodic signals of approximately 1 hz (since the resting heart rate of a healthy adult is between 55 and 70 beats per minute). the instrument operates in an electrical environment that is very noisy with a frequency of 60 hz. it is desirable to have a low-pass filter that will block any noise above 12 hz. a low-pass rl filter can be built using available 50 h inductors; a low-pass rc filter can be built using available 4.2 μf capacitors; resistors of any necessary value are also available. before designing the filter, one must understand the relationship between the output voltage of the circuit and the frequency. for a series rl circuit, how do the impedances of the circuit elements depend on the frequency? select the correct answer. a. the magnitude of the impedance of the resistor increases when the frequency increases: the magnitude of the impedance of the inductor decreases when the frequency increases b. the magnitude of the impedance of the resistor is independent of the frequency: the magnitude of the impedance of the inductor increases when the frequency increases. c. the magnitude of the impedance of the resistor increases when the frequency increases: the magnitude of the impedance of the inductor is independent of the frequency. d. the magnitude of the impedance of the resistor is independent of the frequency: the magnitude of the impedance of the inductor decreases when the frequency increases. e. both impedance magnitudes are independent of the frequency.