Free AC Through Resistor, Capacitor and Inductor MCQs with Answers

• A. Natural resonance
• B. Mechanical resonance
• C. Free resonance
• D. Electrical resonance

Explanation: Tuning a radio is the best example of electrical resonance. When we turn the knob of a radio to tune a station, we are changing the…

• A. 10 joule
• B. 0.1 joule
• C. 0.01 joule
• D. 1.0 joule

Explanation: Using the formula for energy stored in magnetic field of a coil (E = ½ × L × I²)E = ½ × L × I² E = ½ × (50 × 10-3) × (2)² = 0.1 J

• A. The voltage leads current by 900
• B. The voltage leads current by 1800
• C. The current leads voltage by 900
• D. The current and voltage are in phase

Explanation: In A.C capacitive circuits, the current leads the voltage by 90° because first, the current flows through the two plates of the capacitor…

• A. P > V°l°
• B. <P>= V°I° sinθl°
• C. <P>= V°I° Cos θl
• D. <P>= zero

Explanation: In purely inductive or purely capacitive circuit, power loss is zero.

• A. By increasing the frequency of AC
• B. By decreasing the frequency of AC
• C. Does not depend upon the frequency of the AC voltage
• D. None of these

Explanation: Capacitive reactance (Xc) is inversely proportional to the frequency of the AC voltage.

• A. 94.2
• B. 1.57
• C. 157
• D. 9,421

Explanation: Inductive reactance is the opposition offered by the inductor in the AC circuit to the flow of AC current.

• A. resistive circuit
• B. capacitive circuit
• C. inductive circuit
• D. resonant circuit

Explanation: At low frequencies, the series circuit is capacitive as Xc>Xl, but at higher frequencies, the series circuit is inductive as Xl>Xc.

• A. CRO (Cathode Ray Oscilloscope)
• B. Diode
• C. Transistor
• D. Radio

Explanation: The correct answer is CRO (Cathode Ray Oscilloscope). A CRO is designed to visually display the waveform of electrical signals, allowing…

• A. 125W
• B. 160W
• C. 250W
• D. 500W

Explanation: To find the mean power developed by the current in the resistive load, we first calculate the peak value of the current, which is 3.53.

• A. In-phase
• B. Current leads voltage by 90o
• C. Voltage leads current by 90o
• D. Current leads voltage by 180o

Explanation: It can be seen that the phase at O is zero and the phase at the upper maximum is π/2.

• A. Leads the voltage by one-half of a cycle
• B. Leads the voltage by one-fourth of a cycle
• C. Lags the voltage by one-half of a cycle
• D. Is in phase with the voltage

Explanation: In a purely resistive circuit, the current and voltage are in phase with each other.

• A. Effect in charging battery
• B. Effect in charging capacitor
• C. Heating effect through a resistance
• D. Effect passing through an inductance

Explanation: The correct option is Effect in charging battery. Both AC and DC can charge a battery, but typically AC is converted to DC for this…

• A. Volt-second/ampere
• B. Volt/second
• C. Ohm
• D. Ampere volt/second

Explanation: The unit "henry" (H) is used to measure inductance in the International System of Units (SI).

• A. 1
• B. Greater than 1
• C. Less than 1 but greater than zero
• D. Zero

Explanation: In a purely inductive circuit, the average power dissipated is zero. This is because the current and voltage are 90 degrees out of phase…

• A. Increase
• B. Initially increase than decrease
• C. Remain the same
• D. Decrease

Explanation: When the iron core is removed from a coil, transforming it into an air-cored coil, the inductance of the coil will decrease.

• A. Pure capacitive circuit
• B. Pure inductive circuit
• C. RLC series AC circuit at resonance
• D. Both (A) & (8) are true

Explanation: In a pure capacitive circuit, the alternating voltage and current have a phase difference of 90 degrees with each other.