This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 17 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 17 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. An ac circuit consists of an inductor of inductance 0.5 H and a capacitor of capacitance 8 mF in series. The current in the circuit is maximum when the angular frequency of ac source is A) 500 rad/sec. B) 2 x 10$^{5}$ rad/sec. C) 4000 rad/sec. D) 5000 rad/sec. Show Answer Correct Answer: A) 500 rad/sec. 2. How does the frequency of an AC signal affect the reactance of a capacitor? A) Reactance is unaffected by frequency changes. B) Lower frequency results in higher capacitance. C) The frequency of an AC signal inversely affects the reactance of a capacitor; higher frequency results in lower reactance. D) Higher frequency increases reactance. Show Answer Correct Answer: C) The frequency of an AC signal inversely affects the reactance of a capacitor; higher frequency results in lower reactance. 3. Which EM wave has the longest wavelength? A) Radio waved. B) Infrared waves. C) Blue light waves. D) Gama waves. Show Answer Correct Answer: A) Radio waved. 4. The maximum instantaneous value measured from zero value is known as? A) Peak value. B) Peak to peak value. C) Cycle. D) Period. Show Answer Correct Answer: A) Peak value. 5. What does RMS stand for in electrical terms? A) Root Mean Standard. B) Relative Mean Square. C) Radial Mean Square. D) Root Mean Square. Show Answer Correct Answer: D) Root Mean Square. 6. What does the term 'amplitude' refer to in an AC waveform? A) The number of cycles per second. B) The maximum voltage or current value. C) The time taken for one complete cycle. D) The phase difference between two waveforms. Show Answer Correct Answer: B) The maximum voltage or current value. 7. What is the role of the neutral wire in a circuit? A) To carry current to the appliance. B) To carry current away from the appliance. C) To connect the appliance to the earth. D) To increase the voltage. Show Answer Correct Answer: B) To carry current away from the appliance. 8. The true power in a circuit with a current of 4A that passes through a 50$\Omega$ resistor is ..... A) 200W. B) 800W. C) 600W. D) 400W. Show Answer Correct Answer: B) 800W. 9. What is the voltage stepped up to for transmission across the UK? A) 400, 000 volts (400kV). B) 300, 000 volts (300kV). C) 500, 000 volts (500kV). D) 600, 000 volts (600kV). Show Answer Correct Answer: A) 400, 000 volts (400kV). 10. Which one of the below is NOT an AC device? A) Washing machine. B) Fridge. C) Drill machine. D) Microwave. Show Answer Correct Answer: C) Drill machine. 11. AC is preferred over DC because A) AC voltages can be easily and efficiently converted from one voltage to the other by means of transformers. B) Electrical energy (AC)can be transmitted economically over long distances. C) AC circuits exhibit characteristics which are exploited in many devices of daily use. D) All the above. Show Answer Correct Answer: D) All the above. 12. In a series LCR circuit voltages across resistor, Capacitor and Inductor are 10 V, 10 V and 20 V respectively. The source voltage is A) $10\sqrt{2}$. B) 20 V. C) 40 V. D) $10\sqrt{6}$. Show Answer Correct Answer: A) $10\sqrt{2}$. 13. Define the term 'peak voltage' in the context of AC. A) The average voltage level in an AC waveform. B) The minimum voltage level in an AC waveform. C) The maximum voltage level in an AC waveform. D) The voltage level at which AC frequency peaks. Show Answer Correct Answer: C) The maximum voltage level in an AC waveform. 14. What is the phase difference between current and voltage when a capacitor is connected to ac voltage? A) 0. B) 60. C) 90. D) 180. Show Answer Correct Answer: C) 90. 15. Instantaneous power is defined as A) The product of instantaneous current and voltage. B) The product of rms current and voltage. C) The product of peak current and voltage. D) Specific power. Show Answer Correct Answer: A) The product of instantaneous current and voltage. 16. What is the voltage at any particular point in an alternating current called? A) Instantaneous value. B) Average value. C) Peak value. D) Peak-to-peak value. Show Answer Correct Answer: A) Instantaneous value. 17. How does the transformer work with AC? A) A transformer only works with DC current. B) A transformer generates electricity without any coils. C) A transformer uses thermal conduction to transfer energy. D) A transformer works with AC by using electromagnetic induction to transfer energy between coils. Show Answer Correct Answer: D) A transformer works with AC by using electromagnetic induction to transfer energy between coils. 18. State whether the following statements is TRUE or FALSE; An electromagnetic wave consists of electric and magnetic fields. A) TRUE. B) FALSE. C) All the above. D) None of the above. Show Answer Correct Answer: A) TRUE. 19. The function of a generator is to change ..... A) Mechanical energy to electrical energy. B) Electrical energy to mechanical energy. C) Electrical energy to chemical energy. D) Chemical energy to electrical energy. Show Answer Correct Answer: A) Mechanical energy to electrical energy. 20. What is the standard frequency of AC in most countries? A) 40 Hz. B) 50 Hz or 60 Hz. C) 100 Hz. D) 70 Hz. Show Answer Correct Answer: B) 50 Hz or 60 Hz. 21. Which type of current is used in torches A) Alternating Current (AC). B) Direct Current (DC). C) All the above. D) None of the above. Show Answer Correct Answer: B) Direct Current (DC). 22. According to the power triangle, the apparent power is ..... A) Less than the true power. B) Greater than the true power. C) Less than the reactive power. D) Equal to the reactive power. Show Answer Correct Answer: B) Greater than the true power. 23. The value of current flowing through the resistor connected in the secondary A) 0.6 A. B) 0.2 A. C) 2 A. D) 3A. Show Answer Correct Answer: B) 0.2 A. 24. The electric mains supply in our homes and offices is a voltage that varies like a sine function with time such a voltage is called A and the current driven by it in a circuit is called the B.Here, A and B refer to A) DC voltage, AC current. B) AC voltage, DC current. C) AC voltage, DC voltage. D) AC voltage, AC current. Show Answer Correct Answer: D) AC voltage, AC current. 25. Apparent value of ac is A) Mean value for full cycle. B) Mean value for half cycle. C) Rms value. D) All. Show Answer Correct Answer: C) Rms value. ← 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