This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 28 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 28 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Through which material will magnetic lines of force pass the most readily? A) Copper. B) Iron. C) Aluminum. D) None of the above. Show Answer Correct Answer: B) Iron. 2. DC stands for ..... and is used in batteries. A) Distant Current. B) Don't Current. C) Direct Current. D) None of the above. Show Answer Correct Answer: C) Direct Current. 3. A half-wave rectification circuit needs only ..... diode. A) 1. B) 2. C) 3. D) 4. Show Answer Correct Answer: A) 1. 4. How does resistance affect a circuit? A) The relationship of the resistance and a circuit is indirect. B) The relationship of the resistance and a circuit is direct. C) All the above. D) None of the above. Show Answer Correct Answer: A) The relationship of the resistance and a circuit is indirect. 5. This occurs when 2 objects are rubbed together. A) Friction. B) Repel. C) Attract. D) Induction. Show Answer Correct Answer: A) Friction. 6. What is the main difference between alternating current (a.c.) and direct current (d.c.)? A) C. flows in one direction only. B) C. changes direction periodically. C) C. changes direction periodically. D) C. flows in both directions. Show Answer Correct Answer: B) C. changes direction periodically. 7. An LCR series circuit, connected to a source $\epsilon$ A) The voltage across R is zero. B) The voltage across R equals applied voltage. C) The voltage across C is zero. D) The voltage across C equals applied voltage. Show Answer Correct Answer: B) The voltage across R equals applied voltage. 8. Inductive reactance increases as the ..... A) Frequency increases. B) Frequency decreases. C) Impedance increases. D) Impedance decreases. Show Answer Correct Answer: A) Frequency increases. 9. The r.m.s value of an alternating current is given by steady (D.C) current which when flowing through a given circuit for a given time produces A) The more heat than produced by A.C when flowing through the sam circuit. B) The less heat than produced by A.C when flowing through the sam circuit. C) The same heat than produced by A.C when flowing through the same circuit. D) None of the above. Show Answer Correct Answer: C) The same heat than produced by A.C when flowing through the same circuit. 10. The number of instantaneous values between zero and the peak value is A) Zero. B) One. C) Eleven. D) Infinity. Show Answer Correct Answer: D) Infinity. 11. In general, in an alternating circuit A) The average value of current is zero. B) The average value of the square of the current is zero. C) The average power dissipation is zero. D) The phase difference between current and voltage is zero. Show Answer Correct Answer: A) The average value of current is zero. 12. A pure inductor of inductance 0.20 H and a resistor of resistance 200 $\Omega$ A) 1.1 A. B) 8.8 A. C) 9.3 A. D) 10 A. Show Answer Correct Answer: A) 1.1 A. 13. Impedance becomes minimum when: A) XL > XC. B) XL < XC. C) XL = XC. D) R = 0. Show Answer Correct Answer: C) XL = XC. 14. What is the main difference between single-phase and three-phase waveforms? A) Single-phase has three wires, three-phase has one wire. B) Single-phase has one waveform, three-phase has three waveforms. C) Single-phase is used for industrial purposes, three-phase is for residential. D) Single-phase is more efficient than three-phase. Show Answer Correct Answer: B) Single-phase has one waveform, three-phase has three waveforms. 15. At higher frequencies, which of the following plays a dominant role in RLC series circuit A) Resistor. B) Capacitor. C) Inductor. D) Transistor. Show Answer Correct Answer: C) Inductor. 16. What is the frequency of an AC waveform that completes 20 cycles per half second? A) 10Hz. B) 20Hz. C) 30Hz. D) 40Hz. Show Answer Correct Answer: D) 40Hz. 17. At resonance, find the value of current A) 22.52 A. B) 14.14 A. C) 47.41 A. D) 50.25 A. Show Answer Correct Answer: B) 14.14 A. 18. An electric current always produces ..... A) Capacitive reactance. B) A magnetic field. C) Mutual inductance. D) High voltage. Show Answer Correct Answer: B) A magnetic field. 19. A series circuit consists of R = 20 $\Omega$, L = 20 mH, and AC supply 60 V with f = 100 Hz. The voltage drop across L is A) 39.1 V. B) 31.9 V. C) 45.5 V. D) 50.5 V. Show Answer Correct Answer: B) 31.9 V. 20. $\frac{10\angle-10}{5\angle30}$ A) $2\angle-40$. B) $5\angle20$. C) All the above. D) None of the above. Show Answer Correct Answer: A) $2\angle-40$. 21. A student observes that the lights in their house flicker when a large appliance is turned on. What could be the reason? A) The appliance is using DC power. B) The appliance is drawing a large amount of AC current, causing voltage fluctuations. C) The lights are faulty. D) The house wiring is made of plastic. Show Answer Correct Answer: B) The appliance is drawing a large amount of AC current, causing voltage fluctuations. 22. The frequency of direct current (DC) is: A) 0 Hz. B) 50 Hz. C) 60 Hz. D) 100 Hz. Show Answer Correct Answer: A) 0 Hz. 23. The distance that a signal's energy can travel in the time it takes for one cycle to occur is called the signal's: A) Amplitude. B) Frequency. C) Wavelength. D) Period. Show Answer Correct Answer: C) Wavelength. 24. In an AC circuit, if the voltage is given by v=5.0 sin(628t), what is the peak voltage? A) 5.0 V. B) 2.5 V. C) 0 V. D) 10 V. Show Answer Correct Answer: A) 5.0 V. 25. What does the Q-factor measure in a circuit? A) Voltage. B) Current. C) Sharpness of resonance. D) Power. Show Answer Correct Answer: C) Sharpness of resonance. ← 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