This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 20 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 20 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. State whether the following statement is TRUE or FALSE; Electromagnetic waves require a medium to propagate. A) TRUE. B) FALSE. C) All the above. D) None of the above. Show Answer Correct Answer: B) FALSE. 2. In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of supply. Which of the following elements are likely to constitute the circuit? A) Only resistor. B) Resistor and inductor. C) Resistor and capacitor. D) Only inductor. Show Answer Correct Answer: C) Resistor and capacitor. 3. What is the role of a fuse in an AC circuit? A) A fuse protects the circuit by breaking the connection when current exceeds a certain level. B) A fuse is used to convert AC to DC. C) A fuse has no effect on circuit safety. D) A fuse amplifies the current in the circuit. Show Answer Correct Answer: A) A fuse protects the circuit by breaking the connection when current exceeds a certain level. 4. An alternating current source of frequency 100 Hz is joined to a combination of a resistance, a capacitance and a coil in series. The potential difference across the coil, the resistance and the capacitor is 46, 8 and 40 volt respectively. The electromotive force of alternating current source in volt is ..... A) 94. B) 14. C) 10. D) 76. Show Answer Correct Answer: C) 10. 5. In a series RLC circuit, what occurs at resonance? A) Current is at its minimum. B) Power factor is zero. C) Voltage and current are in phase. D) Impedance is at its maximum. Show Answer Correct Answer: C) Voltage and current are in phase. 6. What is the primary difference between AC and DC? A) DC flows in one direction. B) AC has a constant voltage. C) AC flows in one direction. D) DC has a variable voltage. Show Answer Correct Answer: A) DC flows in one direction. 7. What is the condition for resonance in a series RLC circuit? A) The condition for resonance is XL > XC. B) The condition for resonance is R = 0. C) The condition for resonance is XL = XC. D) The condition for resonance is R = XL. Show Answer Correct Answer: C) The condition for resonance is XL = XC. 8. Hot wire ammeters can measure A) Only ac. B) Only dc. C) Both ac and dc. D) Neither ac nor dc. Show Answer Correct Answer: C) Both ac and dc. 9. In a circuit containing resistance only, the voltage and current are ..... with oneanother. A) Together. B) Within range. C) In phase. D) Full rotation. Show Answer Correct Answer: C) In phase. 10. Which quantity determines opposition offered by AC due to inductance? A) Resistance. B) Capacitance. C) Inductive reactance. D) Power factor. Show Answer Correct Answer: C) Inductive reactance. 11. Which household device converts AC to DC for its operation? A) Electric kettle. B) Laptop charger. C) Ceiling fan. D) Toaster. Show Answer Correct Answer: B) Laptop charger. 12. Describe the behavior of an inductor in an AC circuit. A) An inductor in an AC circuit causes the current to lead the voltage by 90 degrees. B) An inductor in an AC circuit causes the current to lag behind the voltage by 90 degrees and opposes changes in current. C) An inductor in an AC circuit has no effect on the phase relationship between current and voltage. D) An inductor in an AC circuit allows current to flow freely without any opposition. Show Answer Correct Answer: B) An inductor in an AC circuit causes the current to lag behind the voltage by 90 degrees and opposes changes in current. 13. Explain the phase difference between voltage and current in an inductive circuit. A) Voltage and current are in phase with each other. B) The current leads the voltage by 90 degrees. C) In an inductive circuit, the current lags the voltage by 90 degrees. D) The current lags the voltage by 180 degrees. Show Answer Correct Answer: C) In an inductive circuit, the current lags the voltage by 90 degrees. 14. Explain the concept of RMS voltage in an AC circuit. A) RMS voltage is the peak voltage in an AC circuit. B) RMS voltage is the average of instantaneous voltages in an AC circuit. C) RMS voltage is the effective voltage in an AC circuit, calculated as the square root of the average of the squares of instantaneous voltages. D) RMS voltage is the total voltage in a DC circuit. Show Answer Correct Answer: C) RMS voltage is the effective voltage in an AC circuit, calculated as the square root of the average of the squares of instantaneous voltages. 15. The current/voltage that changes direction with time are A) AC current. B) DC current. C) All the above. D) None of the above. Show Answer Correct Answer: A) AC current. 16. What happens to the power dissipated in a resistor when the r.m.s. current increases? A) It remains constant. B) It decreases. C) It becomes zero. D) It increases. Show Answer Correct Answer: D) It increases. 17. What is the configuration of components in a series LCR circuit? A) Parallel. B) Series. C) Mixed. D) None. Show Answer Correct Answer: B) Series. 18. An increase in which of the following factors will cause an increase in the inductive reactance of a circuit? A) Inductance and frequency. B) Resistance and voltage. C) Resistance and capacitive reactance. D) None of the above. Show Answer Correct Answer: A) Inductance and frequency. 19. What is the primary function of a resistor in an AC circuit? A) To increase current flow in the circuit. B) To store electrical energy for later use. C) To limit current and control voltage levels. D) To convert AC to DC voltage. Show Answer Correct Answer: C) To limit current and control voltage levels. 20. How does the length of the conductor affect the emf generated? A) Longer conductors generate less emf. B) It has no effect on the emf. C) Longer conductors generate more emf. D) Shorter conductors generate maximum emf. Show Answer Correct Answer: C) Longer conductors generate more emf. 21. What is the function of the fuse in a plug? A) To increase current. B) To decrease voltage. C) To protect the appliance from excess current. D) To connect the appliance to the earth. Show Answer Correct Answer: C) To protect the appliance from excess current. 22. What type of electric current moves from the positive polarity to a negative polarity and moves forward at all times? A) Direct Currents. B) Alternating Currents. C) All the above. D) None of the above. Show Answer Correct Answer: A) Direct Currents. 23. What happens to a light bulb when alternating current reverses direction? A) It turns off. B) It flickers. C) It glows continuously. D) It stops glowing. Show Answer Correct Answer: C) It glows continuously. 24. Equation of power factor A) Cos phi. B) Sin phi. C) Tan phi. D) Cot phi. Show Answer Correct Answer: A) Cos phi. 25. How does the use of AC impact electrical safety? A) AC can increase the risk of electric shock and requires proper safety measures to mitigate hazards. B) AC does not require any safety measures. C) AC is safer than DC in all situations. D) AC eliminates the risk of electric shock. Show Answer Correct Answer: A) AC can increase the risk of electric shock and requires proper safety measures to mitigate hazards. ← 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