This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 25 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 25 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What is the current flow in a purely resistive AC circuit if the resistance is 15 ohms and the voltage is 150V? A) 10A. B) 14A. C) 18A. D) 22A. Show Answer Correct Answer: A) 10A. 2. Which quantity decides heating effect in AC? A) Peak current. B) Average current. C) RMS current. D) Instantaneous current. Show Answer Correct Answer: C) RMS current. 3. Lenz' law is in accordance with the law of conservation of A) Mass. B) Energy. C) Momentum. D) Charge. Show Answer Correct Answer: B) Energy. 4. Why is AC preferred over DC for transmitting electricity over long distances? A) AC is more expensive. B) AC can be easily transformed to different voltages. C) DC is safer. D) DC is more efficient. Show Answer Correct Answer: B) AC can be easily transformed to different voltages. 5. The use of inductor? A) Passive component that store food in a fridge when electric current flows through it. B) Passive component that store energy in a magnetic field when electric current flow through it. C) Passive component that store electric charge in an AC circuit. D) Passive component that limit the current flow. Show Answer Correct Answer: B) Passive component that store energy in a magnetic field when electric current flow through it. 6. Fill in the blank:Hair growth will be lighter in ..... A) Colour. B) Length. C) Texture. D) Volume. Show Answer Correct Answer: A) Colour. 7. A light bulb of resistance $484\, \Omega$ $220\, \text{V}$ A) $0.64\, \text{A}$. B) $0.45\, \text{A}$. C) $0.31\, \text{A}$. D) $1.28\, \text{A}$. Show Answer Correct Answer: A) $0.64\, \text{A}$. 8. What is the role of slip rings in an AC generator? A) To convert AC to DC. B) To maintain electrical contact with the rotating coil. C) To increase the voltage output. D) To reduce electrical noise. Show Answer Correct Answer: B) To maintain electrical contact with the rotating coil. 9. A pure inductor is connected to an AC power supply. In this circuit, the current A) Leads the voltage by 90$^\circ$. B) Lags the voltage by 90$^\circ$. C) Is in phase with the voltage. D) None of the given answers. Show Answer Correct Answer: B) Lags the voltage by 90$^\circ$. 10. What is the step-down turns ratio of a transformer with 200 turns in the primary and 100 turns in the secondary? A) 1:2. B) 2:1. C) 2:2. D) 3:4. Show Answer Correct Answer: B) 2:1. 11. In an ideal inductor, what is the power consumed? A) Maximum. B) Minimum. C) Zero. D) Variable. Show Answer Correct Answer: C) Zero. 12. At resonance, circuit behaves like: A) Capacitor. B) Inductor. C) Pure resistor. D) Open circuit. Show Answer Correct Answer: C) Pure resistor. 13. A 230V, 50Hz voltage is applied to a coil having L = 5H and R = 2 Ohm in series with capacitance C. When the voltage across the coil is 400V, find the current in the circuit? A) 0.1465 A. B) 0.1578 A. C) 0.2547 A. D) 0.4583 A. Show Answer Correct Answer: C) 0.2547 A. 14. In an AC circuit, what is the effect of a resistor? A) Generates magnetic fields. B) Increases voltage. C) Stores electrical energy. D) Opposes the flow of current. Show Answer Correct Answer: D) Opposes the flow of current. 15. Which of the following is a correct safety procedure when unplugging an AC appliance? A) Pull the cord sharply. B) Hold the plug firmly and pull it out. C) Use wet hands. D) Touch the metal prongs. Show Answer Correct Answer: B) Hold the plug firmly and pull it out. 16. Alternating current is represented by A) Sine wave. B) Triangular wave. C) Square wave. D) All of the above. Show Answer Correct Answer: D) All of the above. 17. A 50 Hz AC is flowing in a 14 mH coil. The reactance of the circuit is A) 15 $\Omega$. B) 7.5 $\Omega$. C) 8.8 $\Omega$. D) 4.4 $\Omega$. Show Answer Correct Answer: D) 4.4 $\Omega$. 18. What is the role of inductance in AC circuits? A) Inductance only affects DC circuits. B) Inductance opposes changes in current and causes a phase shift in AC circuits. C) Inductance has no effect on phase shift in AC circuits. D) Inductance increases current flow in AC circuits. Show Answer Correct Answer: B) Inductance opposes changes in current and causes a phase shift in AC circuits. 19. In ac circuit containing R only Voltage and current are not in phase. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 20. What is the voltage level after the step-down transformer connected to the generator? A) 11kV. B) 33kV. C) 132kV. D) 275kV. Show Answer Correct Answer: A) 11kV. 21. The type of current where charges flow in one direction A) Direct Current. B) Alternating Current. C) All the above. D) None of the above. Show Answer Correct Answer: A) Direct Current. 22. What is the main benefit of using alternating current? A) It is easy to use a transformer to change the potential difference. B) It is easy to use a transformer to change the frequency. C) It is easy to use a transformer to change the current. D) It is easy to use a transformer to change the resistance. Show Answer Correct Answer: A) It is easy to use a transformer to change the potential difference. 23. What does a Band Stop filter do? A) Blocks low frequency signals. B) Blocks high frequency signals. C) Allows a specific range of signals. D) Blocks a specific range of signals. Show Answer Correct Answer: D) Blocks a specific range of signals. 24. Typical application for zener diodes is as A) Full-wave rectifiers. B) Half-wave rectifiers. C) Voltage regulators. D) None of the above. Show Answer Correct Answer: C) Voltage regulators. 25. An inductor is connected to a source of ac voltage. The alternating voltage ..... alternating current by a phase angle of ..... radians A) Lags, $\frac{\pi}{2}$. B) Leads, $\frac{\pi}{2}$. C) In same phase with, 0. D) Leads, $\phi$. Show Answer Correct Answer: B) Leads, $\frac{\pi}{2}$. ← 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