Electrical Engineering is part of Engineering and holds 3,646 questions with answers, free to read and with no account needed.
Attempt each question before revealing the answer, and keep a note of the ones you get wrong — those are the topics worth reading about properly. If an answer looks wrong, there is a link to report it on every question.
Answer: A. Minimum
At parallel resonance, the total impedance of the tank circuit reaches its absolute maximum possible value. Ohm's law dictates that a maximum circuit impedance must result in a minimum line current drawn. The external so...
Answer: B. Buchholz relay
Buchholz relays are specialized mechanical protective devices designed to detect internal faults in oil-filled transformers. Large power transformers justify the cost of advanced gas-actuated Buchholz relay protection sy...
Answer: B. Resistive
At resonance, inductive reactance and capacitive reactance are equal in magnitude but opposite in phase characteristics. These opposing reactive voltages cancel each other out entirely across the terminals of the resonan...
Answer: B. Decreases
Quality factor or Q factor measures the selectivity and sharpness of a resonant LC network. Bandwidth is inversely proportional to the quality factor in tuned electronic circuits. Therefore an increase in the Q factor re...
Answer: A. Inductive
Operating below the resonant frequency causes the inductive reactance to decrease while capacitive reactance increases. The larger capacitive reactance draws less current than the smaller inductive branch in a parallel n...
Answer: A. Equal to but opposite in phase to
At series resonance, inductive reactance and capacitive reactance cancel each other out because their magnitudes are equal. Current flowing through the series circuit creates voltages across the inductor and capacitor th...
Answer: C. Minimum
Series resonance causes inductive and capacitive reactances to cancel out, leaving only the small internal resistance. This complete cancellation of reactive components minimizes the total opposition to current flow in t...
Answer: A. Very large
At parallel resonance the dynamic impedance of the tank circuit is calculated as L over CR. Typical circuit parameters result in a high inductance to capacitance resistance product ratio. Consequently this ratio evaluate...
Answer: A. Zero
At series resonance, the inductive reactance and capacitive reactance cancel each other out completely in the circuit. This exact cancellation results in a net reactive component value that evaluates strictly to zero ohm...
Answer: A. IF
Intermediate frequency stages in superheterodyne receivers require precise bandpass filtering to achieve high selectivity. Double-tuned filter circuits use coupled LC resonators to provide a flat passband and steep rejec...
Answer: C. 1
At either series or parallel resonance, inductive reactance and capacitive reactance cancel each other out completely. This exact cancellation leaves only pure resistance in the AC circuit, eliminating any phase angle en...
Answer: B. Zero
At parallel resonance inductive and capacitive reactances are equal in magnitude. Currents flowing through the inductor and capacitor are equal and flow in opposite phase directions. This phase opposition causes the net...
Answer: C. High thermal conductivity
High thermal conductivity is not strictly essential for materials utilized in transformer iron cores. Core materials focus primarily on magnetic properties like low hysteresis loss, high permeability, and low reluctance....
Answer: A. Radio frequency
Tuned amplifiers use resonant circuits to select and amplify narrow bands of high frequency radio signals. Radio frequency applications require precise frequency discrimination to separate multiple transmitting channels...
Answer: C. 0o
During parallel resonance, the phase angle between the circuit current and source voltage is exactly zero degrees. Inductive and capacitive reactances cancel each other out completely at the resonant operating frequency...
