This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 8 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 8 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. A.C. power is transmitted from a power house at a high voltage as A) The rate of transmission is faster at high voltages. B) It is more economical due to less power loss. C) Power cannot be transmitted at low voltages. D) A precaution against theft of transmission lines. Show Answer Correct Answer: B) It is more economical due to less power loss. 2. Alternating current means the current flows from negative to positive. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 3. In the UK, what is the mains frequency of the alternating current? A) 50 Hz. B) 60 Hz. C) 100 Hz. D) 120 Hz. Show Answer Correct Answer: A) 50 Hz. 4. The relationship between two alternating quantities can be represented by using A) Phasor diagram. B) Sinusoidal graph. C) Phasor diagram and sinusoidal graph. D) None of above. Show Answer Correct Answer: C) Phasor diagram and sinusoidal graph. 5. Which of the following are commonly used as rectifiers in electrical circuits? A) Anodes. B) Cathodes. C) Diodes. D) None of the above. Show Answer Correct Answer: C) Diodes. 6. Fill in the blank:Alternating current is the quickest method of hair removal, as an increased number of hairs can be treated within a short period of time when compared with the ..... method. A) Blend. B) Laser. C) Waxing. D) Shaving. Show Answer Correct Answer: A) Blend. 7. Voltage and current is an AC circuit are given by $V=5\\sin\left(100\pi t-\frac{\pi}{6}\right)$ $I=6\\sin\left(100\pi t+\frac{\pi}{6}\right)$ A) Voltage leads the current by $30^o$. B) Current leads the voltage by $30^o$. C) Voltage leads the current by $60^o$. D) Current leads the voltage by $60^o$. Show Answer Correct Answer: D) Current leads the voltage by $60^o$. 8. Average power dissipated in an ideal inductor in a.c. circuit is: A) Infinite. B) Zero. C) 100. D) One. Show Answer Correct Answer: B) Zero. 9. What is the effect of increasing frequency on the impedance of a capacitor? A) Impedance of a capacitor is constant regardless of frequency. B) Increasing frequency has no effect on the impedance of a capacitor. C) Increasing frequency increases the impedance of a capacitor. D) Increasing frequency decreases the impedance of a capacitor. Show Answer Correct Answer: D) Increasing frequency decreases the impedance of a capacitor. 10. Explain the concept of resonance in AC circuits. A) Resonance occurs when the circuit is short-circuited. B) Resonance happens only in DC circuits. C) Resonance in AC circuits is the condition where inductive and capacitive reactances are equal, resulting in maximum current at the resonant frequency. D) Resonance is the point where resistance is minimized in a circuit. Show Answer Correct Answer: C) Resonance in AC circuits is the condition where inductive and capacitive reactances are equal, resulting in maximum current at the resonant frequency. 11. In which circuit voltage leads current? A) Pure resistor. B) Pure inductor. C) Pure capacitor. D) Resonant RLC. Show Answer Correct Answer: C) Pure capacitor. 12. Sharpness is more when A) R is large. B) R is small. C) XL is small. D) Bandwidth is large. Show Answer Correct Answer: B) R is small. 13. AC generators works based on A) Faraday's Law. B) Lenz Law. C) Newton's Law. D) Electrostatic law. Show Answer Correct Answer: A) Faraday's Law. 14. An AC power supply is giving 120 Vrms, what is the average DC voltage for this power supply? A) 120 V. B) 169.7 V. C) 100 V. D) 220 V. Show Answer Correct Answer: A) 120 V. 15. A wall socket in Europe gives 120V RMS voltage, What is the peak voltage used in Europe? A) 89 V. B) 120 V. C) 170 V. D) 220 V. Show Answer Correct Answer: C) 170 V. 16. Frequency is 1/period and period is 1/frequency? True or false? A) YEA baby. B) Not until i meet you. C) Only when the moon is full. D) None of the above. Show Answer Correct Answer: A) YEA baby. 17. Peak-to-peak, Peak, RMS, and Average are four forms of measurement of voltage and current associated with sine waves. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 18. Advantages of DC are A) Most equipment are more efficient when directly powered from DC. B) Less risks of shock hazard for voltages below 48 Volts. C) More efficient. D) All the above. Show Answer Correct Answer: D) All the above. 19. What is the main characteristic of alternating current? A) It is used in flashlights. B) It is provided by batteries. C) It flows in one direction. D) It reverses direction. Show Answer Correct Answer: D) It reverses direction. 20. How does AC differ from direct current (DC)? A) AC differs from DC in that it alternates direction, while DC flows in one direction. B) AC is used exclusively in batteries. C) AC is always more efficient than DC. D) DC can be transmitted over long distances without loss. Show Answer Correct Answer: A) AC differs from DC in that it alternates direction, while DC flows in one direction. 21. What is the role of a capacitor in an AC circuit? A) A capacitor converts AC to DC in an AC circuit. B) A capacitor acts as a resistor to limit current flow in an AC circuit. C) A capacitor stores energy, smooths voltage fluctuations, and introduces phase shifts in an AC circuit. D) A capacitor generates electrical power in an AC circuit. Show Answer Correct Answer: C) A capacitor stores energy, smooths voltage fluctuations, and introduces phase shifts in an AC circuit. 22. Magnetic flux of 5 mwb is linked with a coil, when current of 1 mA flows through it, Self-inductance will be A) 1 H. B) 5 H. C) 50 H. D) 20 H. Show Answer Correct Answer: B) 5 H. 23. An electrical element X when connected to an alternating voltage source has current through it leading the voltage by 2radian. Identify X A) Capacitor. B) Resistor. C) Inductor. D) Series LR circuit. Show Answer Correct Answer: A) Capacitor. 24. What is the condition for RCL circuit to oscillate at resonant frequency? A) R & X$_{C }$must be equal. B) R & X$_{L}$ must be equal. C) X$_{C}$ & X$_{L}$ must be equal. D) R, X$_{C}$ & X$_{L}$ must be equal. Show Answer Correct Answer: C) X$_{C}$ & X$_{L}$ must be equal. 25. Choose the wrong statement about the power of an ac circuit A) There are no power dissipated in capacitor and inductor. B) Power is only dissipated in resistor. C) The ratio of real power to apparent power is called the power factor. D) At resonance, power factor is equal to real power. Show Answer Correct Answer: D) At resonance, power factor is equal to real power. ← 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 9Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 10Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 11 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books