This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 21 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 21 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. The voltage drop in the power line is A) 3 kV. B) 2 kV. C) 1.7 kV. D) 2.8 kV. Show Answer Correct Answer: A) 3 kV. 2. The amount of electricity a capacitor can store is directly proportional to the A) Distance between the plates and inversely proportional to the plate area. B) Plate area and is not affected by the distance between the plates. C) Plate area and inversely proportional to the distance between the plates. D) None of the above. Show Answer Correct Answer: C) Plate area and inversely proportional to the distance between the plates. 3. Which will light a lamp more brightly, 12 V peak ac or 12 V steady dc? A) 12 V peak ac. B) 12 V steady dc. C) All the above. D) None of the above. Show Answer Correct Answer: B) 12 V steady dc. 4. The resistance of the ideal conductor is A) Very low. B) Medium. C) High. D) Very high. Show Answer Correct Answer: A) Very low. 5. Capacitance is measured in ..... A) Amperes. B) Henrys. C) Joules. D) Farads. Show Answer Correct Answer: D) Farads. 6. Voltage leads the current in an AC generators can be referred to A) Resistance. B) Capacitance. C) Inductance. D) None of the above. Show Answer Correct Answer: C) Inductance. 7. If frequency of AC source is doubled, the inductive reactance will: A) Become half. B) Become double. C) Remain same. D) Become four times. Show Answer Correct Answer: B) Become double. 8. Alternating current is the current which A) Changes in magnitude only. B) Changes in direction only. C) Changes both in magnitude and direction. D) Neither changes in magnitude nor changes in direction. Show Answer Correct Answer: C) Changes both in magnitude and direction. 9. Which device stores energy in electric field in AC circuit? A) Resistor. B) Inductor. C) Capacitor. D) Generator. Show Answer Correct Answer: C) Capacitor. 10. When an alternating emf flows through an unknown device. it is found that both alternating emf and alternating current are in phase with each other. Identify the device. A) Inductor L. B) Capacitor C. C) Resistor R. D) Both inductor and resistor. Show Answer Correct Answer: C) Resistor R. 11. Electric current that reverses its direction of flow in a regular pattern A) Voltage. B) Direct Current. C) Alternating Current. D) Parallel Circuit. Show Answer Correct Answer: C) Alternating Current. 12. What is the main principle behind the operation of an AC generator? A) Electromagnetic induction. B) Thermal conduction. C) Chemical reaction. D) Mechanical friction. Show Answer Correct Answer: A) Electromagnetic induction. 13. The Phase Angle between Current and Voltage in a LCR circuit is always A) Zero. B) $\pi$. C) $-\frac{\pi}{2}$. D) None of These. Show Answer Correct Answer: D) None of These. 14. The Phase Angle between Current and Voltage in a Resistance circuit is A) 0. B) $\frac{-\pi}{2}$. C) $\frac{\pi}{4}$. D) $+\frac{\pi}{2}$. Show Answer Correct Answer: A) 0. 15. What are the advantages of using AC over DC for power transmission? A) DC is preferred for reducing energy loss in power transmission. B) AC cannot be transformed to high voltages easily. C) AC is less efficient for long-distance transmission than DC. D) AC is advantageous for power transmission because it can be easily transformed to high voltages, reducing energy loss, and is more efficient for long-distance transmission. Show Answer Correct Answer: D) AC is advantageous for power transmission because it can be easily transformed to high voltages, reducing energy loss, and is more efficient for long-distance transmission. 16. Explain the relationship between resonance and frequency in AC circuits. A) Resonance occurs at a fixed frequency in AC circuits. B) Frequency in AC circuits is not related to resonance. C) Resonance only happens in DC circuits. D) Resonance in AC circuits happens at the frequency where inductive and capacitive reactances cancel each other out, resulting in a peak in current flow. Show Answer Correct Answer: D) Resonance in AC circuits happens at the frequency where inductive and capacitive reactances cancel each other out, resulting in a peak in current flow. 17. A transistor oscillator using a resonant circuit with an inductor L and a capacitor C in series produce oscillations of frequency f. If L is doubled and C is changed to 4C, the frequency will be A) 8f. B) $\frac{f}{2\sqrt{2}}$. C) F/2. D) F/4. Show Answer Correct Answer: B) $\frac{f}{2\sqrt{2}}$. 18. To reduce the resonant frequency in an LCR series circuit with a generator A) The generator frequency should be reduced. B) Another capacitor should be added in parallel to the first. C) The iron core of the inductor should be removed. D) Dielectric in the capacitor should be removed. Show Answer Correct Answer: B) Another capacitor should be added in parallel to the first. 19. What does the term 'reactance' refer to in A.C. circuits? A) Resistance to direct current. B) Power consumption. C) Opposition to current flow. D) Opposition to A.C. current. Show Answer Correct Answer: D) Opposition to A.C. current. 20. How does the use of transformers benefit AC power systems? A) They allow for easy conversion of AC to DC. B) They enable efficient voltage transformation for transmission and distribution. C) They increase the frequency of the current. D) They reduce the need for power stations. Show Answer Correct Answer: B) They enable efficient voltage transformation for transmission and distribution. 21. State whether the following statements is TRUE or FALSE;Visible light is not part of the spectrum. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 22. Average power in a purely resistive circuit A) 0. B) VI. C) VI sin phi. D) VI cos phi. Show Answer Correct Answer: B) VI. 23. What is the relationship between voltage and current in reducing energy losses in AC transmission? A) Higher voltage and higher current reduce losses. B) Higher voltage and lower current reduce losses. C) Lower voltage and higher current reduce losses. D) Lower voltage and lower current reduce losses. Show Answer Correct Answer: B) Higher voltage and lower current reduce losses. 24. In an AC circuit, what does the term 'mean voltage' refer to? A) The maximum voltage reached. B) The average voltage over a complete cycle. C) The voltage at the midpoint of the cycle. D) The peak voltage divided by two. Show Answer Correct Answer: B) The average voltage over a complete cycle. 25. Impedance in a LCR circuit at resonance A) 0. B) R. C) Z. D) XL. Show Answer Correct Answer: B) R. ← 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