Quiz for Alternating Current

Q1: What is the average value of AC over a complete cycle?

A. Zero B. Maximum C. Root mean square D. Infinity

Q2: What is the RMS value of an AC current with peak value I₀?

A. I₀/√2 B. I₀ C. 2I₀ D. I₀²

Q3: What is the phase difference between voltage and current in a pure resistor?

A. 0° B. 90° C. 180° D. 45°

Q4: In a pure inductive circuit, the current ______ the voltage.

A. lags B. leads C. equals D. is zero

Q5: In a capacitive AC circuit, current ______ voltage.

A. leads B. lags C. equals D. is zero

Q6: Power consumed in a purely inductive or capacitive AC circuit is:

A. Zero B. Maximum C. Half D. Infinity

Q7: What is the formula for impedance in an L-R circuit?

A. Z = √(R² + (XL)²) B. Z = R + XL C. Z = R - XL D. Z = RXL

Q8: The power factor in an AC circuit is:

A. cos(φ) B. sin(φ) C. tan(φ) D. cot(φ)

Q9: At resonance in an LCR circuit, impedance is:

A. Minimum B. Maximum C. Zero D. Infinite

Q10: Resonance occurs when:

A. XL = XC B. XL > XC C. XL < XC D. XL = R

Q11: Unit of reactance is:

A. Ohm B. Henry C. Farad D. Watt

Q12: Power factor of a purely resistive AC circuit is:

A. 1 B. 0 C. 0.5 D. Infinity

Q13: In an AC generator, the induced emf is maximum when:

A. Magnetic flux is zero B. Rate of change of flux is maximum C. Magnetic field is maximum D. Loop is at rest

Q14: Which device is used to measure AC current?

A. AC ammeter B. Galvanometer C. Voltmeter D. Multimeter

Q15: Lenz’s law is in accordance with the law of:

A. Conservation of energy B. Conservation of charge C. Conservation of momentum D. Conservation of mass

Q16: The frequency of AC in India is:

A. 50 Hz B. 60 Hz C. 25 Hz D. 100 Hz

Q17: Which of the following causes heating in an AC circuit?

A. Resistor B. Inductor C. Capacitor D. Transformer

Q18: Transformer works on which principle?

A. Mutual Induction B. Self Induction C. Electrostatics D. Static Electricity

Q19: Which of the following is not ideal for DC supply?

A. Transformer B. Battery C. DC generator D. Rectifier

Q20: Apparent power is the product of:

A. Voltage and current (RMS) B. Voltage and current (average) C. Only voltage D. Only current