This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 12 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 12 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What is the phase difference between voltage and current in a purely resistive AC circuit? A) 180 degrees. B) 90 degrees. C) 270 degrees. D) 0 degrees. Show Answer Correct Answer: D) 0 degrees. 2. In a circuit containing R and L as the frequency of the impressed AC increases, the impedance of the circuit A) Decreases. B) Increases. C) Remains unchanged. D) First increases and then decreases. Show Answer Correct Answer: B) Increases. 3. What occurs when the conductor moves beyond 180$^\circ$? A) No emf is generated. B) The cycle stops. C) Emf remains constant. D) Emf builds from maximum positive to maximum negative. Show Answer Correct Answer: D) Emf builds from maximum positive to maximum negative. 4. Why is power factor correction important in electrical circuits? A) To increase energy losses and reduce efficiency. B) To make the system less reliable. C) To improve the efficiency of the system and reduce energy losses. D) To decrease the overall power output of the system. Show Answer Correct Answer: C) To improve the efficiency of the system and reduce energy losses. 5. Alternating current cannot be measured by dc ammeter because A) Average value of complete cycle is zero. B) Ac cannot pass through dc ammeter. C) Ac is virtual. D) Ac changes its direction. Show Answer Correct Answer: A) Average value of complete cycle is zero. 6. In a pure inductive circuit, the resistance offered to current is calle A) Resistance. B) Inductive reactance. C) Capacitive reactance. D) Resistance and reactance. Show Answer Correct Answer: B) Inductive reactance. 7. Which current did Tesla believe was the better option? A) Direct current. B) Alternating current. C) All the above. D) None of the above. Show Answer Correct Answer: B) Alternating current. 8. Fill in the blank:Follicles will lie ..... in the skin. A) Shallower. B) Deeper. C) Thicker. D) Higher. Show Answer Correct Answer: A) Shallower. 9. What is the color of the live wire in a mains cable? A) Blue. B) Brown. C) Green. D) Yellow. Show Answer Correct Answer: B) Brown. 10. What is the purpose of the National Grid? A) To generate electricity. B) To distribute electricity efficiently. C) To store electricity. D) To convert electricity to heat. Show Answer Correct Answer: B) To distribute electricity efficiently. 11. The power factor is the ratio of ..... power to ..... power. A) True and apparent. B) True and real. C) Positive and negative. D) Factor and real. Show Answer Correct Answer: A) True and apparent. 12. An LCR series circuit connected to a source E is at resonance. Then the voltage across A) R is zero. B) R equals applied voltage. C) C is zero. D) L equals applied voltage. Show Answer Correct Answer: B) R equals applied voltage. 13. "The direction of an induced e.m.f. is always such that it tends to set up a current opposing the motion or the change of flux responsible for inducing that e.m.f." , this is the statement for? A) Lenz's law. B) Faraday's law. C) Fleming's right hand rule. D) Fleming's left hand rule. Show Answer Correct Answer: A) Lenz's law. 14. In an AC circuit, if the voltage is given by v=10.0 sin(1000t), what is the rms voltage? A) 10.0 V. B) 5.0 V. C) 14.14 V. D) 7.07 V. Show Answer Correct Answer: D) 7.07 V. 15. The potential difference between two conductors which are insulated from each other is measured in A) Volts. B) Amperes. C) Coulombs. D) None of the above. Show Answer Correct Answer: A) Volts. 16. Explain how an oscilloscope can be used to visualize AC signals. A) An oscilloscope visualizes AC signals by displaying their waveforms on a screen, showing amplitude and frequency over time. B) An oscilloscope measures temperature changes in AC signals. C) An oscilloscope amplifies AC signals for better sound quality. D) An oscilloscope converts AC signals into digital audio formats. Show Answer Correct Answer: A) An oscilloscope visualizes AC signals by displaying their waveforms on a screen, showing amplitude and frequency over time. 17. Most of the electrical energy sold by power companies is transmitted and distributed as A) (a) AC power. B) (b) DC power. C) All the above. D) None of the above. Show Answer Correct Answer: A) (a) AC power. 18. What is the difference between the movement of the two electrons between the two types of currents? A) There's no difference. B) An Alternating Currents electrons move in one direction while a Direct Currents electrons move back and forth. C) An Alternating Currents electrons move back and forth while a Direct Currents electrons move in one direction. D) An Alternating Currents electrons move back and forth while a Direct Currents electrons don't move at all. Show Answer Correct Answer: C) An Alternating Currents electrons move back and forth while a Direct Currents electrons move in one direction. 19. In a series resonant circuit, the impedance of the circuit is A) Minimum. B) Maximum. C) Zero. D) None of the above. Show Answer Correct Answer: A) Minimum. 20. An A.C. voltmeter reads 250 volts. The frequency of alternating is 50 Hz, the peak value of voltage is A) 3525.0 volts. B) 35.35 volts. C) 353.5 volts. D) 3.535 volts. Show Answer Correct Answer: C) 353.5 volts. 21. What is the relationship between inductive reactance (XL) and frequency? A) XL decreases with frequency. B) XL is constant. C) XL increases with frequency. D) XL is independent of frequency. Show Answer Correct Answer: C) XL increases with frequency. 22. In a pure capacitor circuit, ..... A) The current leads voltage by $\frac{\pi}{2}$. B) The current and voltage are in phase. C) The voltage leads current by $\frac{\pi}{2}$. D) The current and voltage are in antiphase. Show Answer Correct Answer: A) The current leads voltage by $\frac{\pi}{2}$. 23. What is the formula for series impedance in an RLC circuit? A) $Z=R+\left(X_L+X_C\right)$. B) $Z=\sqrt{R^2+\left(X_L-X_C\right)^2}$. C) $Z=R^2+\left(X_L-X_C\right)^2$. D) None of the above. Show Answer Correct Answer: B) $Z=\sqrt{R^2+\left(X_L-X_C\right)^2}$. 24. A bulb and a capacitor are connected in series to a source of alternating current. If its frequency is increased, while keeping the voltage of the source constant, then bulb will A) Give more intense light. B) Give less intense light. C) Give light of same intensity before. D) Stop radiating light. Show Answer Correct Answer: A) Give more intense light. 25. How is impedance different from resistance in an AC circuit? A) Impedance only includes reactance in an AC circuit. B) Impedance is not relevant in an AC circuit. C) Impedance is the same as resistance in an AC circuit. D) Impedance includes both resistance and reactance. Show Answer Correct Answer: D) Impedance includes both resistance and reactance. ← 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