This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 27 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 27 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Which type of current is used in a microwave A) Alternating Current (AC). B) Direct Current (DC). C) All the above. D) None of the above. Show Answer Correct Answer: A) Alternating Current (AC). 2. What is the main characteristic of direct current? A) It reverses direction. B) It comes from power plants. C) It is used in homes. D) It flows in one direction. Show Answer Correct Answer: D) It flows in one direction. 3. Which of the following is true of the current in a capacitive circuit? A) It leads the voltage. B) It lags the voltage. C) It is the same as the voltage. D) It counteracts the voltage. Show Answer Correct Answer: A) It leads the voltage. 4. What is a key reason for using high voltage in AC transmission lines? A) To increase the speed of electricity flow. B) To reduce energy losses by decreasing current. C) To make the lines more durable. D) To allow for easier maintenance. Show Answer Correct Answer: B) To reduce energy losses by decreasing current. 5. What type of transformer increases the voltage from primary to secondary coil? A) Step-down Transformer. B) Step-up Transformer. C) Isolation Transformer. D) Auto Transformer. Show Answer Correct Answer: B) Step-up Transformer. 6. When the current increases in an AC circuit, what role does inductance play? A) It reduces the current. B) It increases the current. C) It causes the overcurrent protection to open. D) It plays no role at all. Show Answer Correct Answer: A) It reduces the current. 7. A device that uses an electromagnet to measure electric current is a(n) ..... A) Generator. B) Commutator. C) Electric motor. D) Galvanometer. Show Answer Correct Answer: D) Galvanometer. 8. In a pure resistor circuit, ..... A) The voltage and current are in antiphase. B) The voltage leads current by $\frac{\pi}{2}$. C) The voltage and current are in phase. D) The current leads voltage by $\frac{\pi}{2}$. Show Answer Correct Answer: C) The voltage and current are in phase. 9. What does RLC stand for A) Remote Logic Control. B) Resistor Logic Capacitor Circuit. C) Resistor Inductor Capacitor Circuit. D) None of the above. Show Answer Correct Answer: C) Resistor Inductor Capacitor Circuit. 10. The phase angle between current and voltage is A) 50$^\circ$. B) 53$^\circ$4'. C) 55$^\circ$4'. D) 63$^\circ$9'. Show Answer Correct Answer: C) 55$^\circ$4'. 11. Explain the concept of resonance in an RLC circuit. A) Resonance is achieved when the resistance is minimized in the circuit. B) Resonance occurs when the circuit is powered by a DC source. C) Resonance happens when the circuit is open and no current flows. D) Resonance in an RLC circuit is the condition where inductive and capacitive reactances are equal, maximizing current at the resonant frequency. Show Answer Correct Answer: D) Resonance in an RLC circuit is the condition where inductive and capacitive reactances are equal, maximizing current at the resonant frequency. 12. The current flowing in purely capacitive circuit connected with ac source A) Conventional current. B) Electronic current. C) Wattless current. D) None. Show Answer Correct Answer: C) Wattless current. 13. The two windings of a conventional transformer are known as the ..... A) High voltage winding and low voltage winding. B) Primary winding and secondary winding. C) Mutual winding and inductive winding. D) Step-up winding and step-down winding. Show Answer Correct Answer: B) Primary winding and secondary winding. 14. How do transformers step up or step down voltage in AC systems? A) Transformers convert AC to DC to change voltage. B) Transformers rely on magnetic fields to increase or decrease voltage. C) Transformers step up or step down voltage by using the turns ratio of their coils. D) Transformers use capacitors to adjust voltage levels. Show Answer Correct Answer: C) Transformers step up or step down voltage by using the turns ratio of their coils. 15. The relationship between the inductive reactance of an inductor is A) Directly proportional to the frequency of the AC source. B) Inversely proportional to the frequency of the AC source. C) Inversely proportional to the inductance of a inductor. D) None of the above. Show Answer Correct Answer: A) Directly proportional to the frequency of the AC source. 16. What type of current is represented by the following I-t graph A) DC current. B) AC current. C) Pulsating Current. D) Time varying current. Show Answer Correct Answer: B) AC current. 17. What is meant by Alternating Current? A) An electric current whose direction change periodically. B) An electric current whose magnitude change periodically. C) An electric current whose magnitude and direction change periodically. D) An electric current whose magnitude or direction change periodically. Show Answer Correct Answer: C) An electric current whose magnitude and direction change periodically. 18. What happens to the Self-inductance when the current in the coil becomes double its original value? A) Becomes half. B) Becomes four times. C) Becomes infinity. D) No Change. Show Answer Correct Answer: D) No Change. 19. The opposition offered by a coil to the flow of alternating current is called (disregard resistance) A) Impedance. B) Reluctance. C) Inductive reactance. D) None of the above. Show Answer Correct Answer: C) Inductive reactance. 20. Calculate the r.m.s value of a.c if its peak value is 10A A) 2.07A. B) 5.07A. C) 7.07A. D) 9.07A. Show Answer Correct Answer: C) 7.07A. 21. The selectivity of a series LCR AC circuit is large, when A) L is large and R is large. B) L is small and R is small. C) L is large and R is small. D) L = R. Show Answer Correct Answer: C) L is large and R is small. 22. When electrons in the transmitting antenna vibrate 94000 times per second, they produce radio waves having frequency A) 9.4 kHz. B) 940 kHz. C) 94kHz. D) None of these. Show Answer Correct Answer: C) 94kHz. 23. Reactance increases with an increase in ..... A) Resistance. B) Magnetism. C) Capacitance. D) Inductance. Show Answer Correct Answer: D) Inductance. 24. Multimeter used to measure A) AC voltage. B) DC voltage. C) Resistance. D) All of the above. Show Answer Correct Answer: D) All of the above. 25. What is the phase difference between voltage and current in a purely capacitive circuit? A) 0 degrees. B) 90 degrees. C) 180 degrees. D) 270 degrees. Show Answer Correct Answer: B) 90 degrees. ← PreviousNext →Related QuizzesClass 12 Physics (Part I) Chapter 7 Alternating Current Quiz 1Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 2Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 3Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 4Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 5Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 6Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 7Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 8Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 9Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 10 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books