This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 5 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 5 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What are the primary applications of transformers? A) Thermal regulation, mechanical support, and fluid dynamics. B) Power generation, energy storage, and signal amplification. C) Data compression, error detection, and frequency modulation. D) Voltage transformation, circuit isolation, impedance matching, and signal processing. Show Answer Correct Answer: D) Voltage transformation, circuit isolation, impedance matching, and signal processing. 2. The circuit in which current and voltage are in phase, the power factor is: A) Zero. B) One. C) Two. D) Three. Show Answer Correct Answer: B) One. 3. If the frequency of the generator is increased, what happens to the output voltage? A) It becomes zero. B) It decreases. C) It remains constant. D) It increases. Show Answer Correct Answer: D) It increases. 4. A resistor, capacitor and inductor is connected in series with resistance of R = 400 $\Omega$, inductive reactance of X$_{L}$ = 500 $\Omega$ dan impedance of Z = 500 $\Omega$. Calculate the value of capacitive reactance from the capcitor. A) 200 $\Omega$. B) 300 $\Omega$. C) 400 $\Omega$. D) 500 $\Omega$. Show Answer Correct Answer: A) 200 $\Omega$. 5. How does a circuit breaker improve safety in AC household circuits? A) By increasing voltage. B) By automatically cutting off power during faults. C) By storing excess energy. D) By converting AC to DC. Show Answer Correct Answer: B) By automatically cutting off power during faults. 6. The graph of alternating current or alternating voltage is a ..... form. A) Square. B) Sinusoidal. C) Triangle. D) Sawtooth. Show Answer Correct Answer: B) Sinusoidal. 7. What is the effect of increasing frequency on capacitive reactance (XC)? A) XC increases. B) XC becomes zero. C) XC decreases. D) XC remains constant. Show Answer Correct Answer: C) XC decreases. 8. The self-induced voltage across an inductance is produced by a change in ..... A) Current with respect to time. B) Resistance with respect to time. C) Capacitance with respect to time. D) Voltage with respect to time. Show Answer Correct Answer: A) Current with respect to time. 9. In AC generator, emf changes sinusoidally because of: A) Linear motion of coil. B) Uniform rotation of coil. C) Variable magnetic field. D) Constant flux. Show Answer Correct Answer: B) Uniform rotation of coil. 10. The efficiency of power in an AC circuit is expressed by what term? A) True power. B) Apparent Power. C) Power factor. D) None of the above. Show Answer Correct Answer: C) Power factor. 11. Which of the following is a common source of alternating current (AC) in homes? A) Battery. B) Power plant. C) Solar cell. D) Capacitor. Show Answer Correct Answer: B) Power plant. 12. What is the total opposition to AC in a circuit containing resistors, inductors, and capacitors? A) Resistance. B) Reactance. C) Impedance. D) Conductance. Show Answer Correct Answer: C) Impedance. 13. What is the unit of frequency in alternating current? A) Hertz (Hz). B) Joules (J). C) Newtons (N). D) Amperes (A). Show Answer Correct Answer: A) Hertz (Hz). 14. An AC voltage is applied to a resistance R and an inductor L in series. If R and the inductive reactance are both equal to 3 $\Omega$ A) $\frac{\pi}{4}$. B) $\frac{\pi}{2}$. C) Zero. D) $\frac{\pi}{6}$. Show Answer Correct Answer: A) $\frac{\pi}{4}$. 15. What is one complete sequence of voltage or current changes from zero to a positive peak to zero, then through a negative peak and back to zero? A) Cycle. B) A bunch of electrical terms I don't know. C) Who cares?. D) None of the above. Show Answer Correct Answer: A) Cycle. 16. Which device provides direct current? A) Power plant. B) Outlet. C) Battery. D) Light bulb. Show Answer Correct Answer: C) Battery. 17. A current which periodically changes direction and magnitude is known as A) Direct Current. B) Alternating Current. C) Pulsating DC. D) None of the above. Show Answer Correct Answer: B) Alternating Current. 18. What does a Band Pass filter do? A) Blocks low frequency signals. B) Blocks high frequency signals. C) Allows a specific range of signals. D) Blocks a specific range of signals. Show Answer Correct Answer: C) Allows a specific range of signals. 19. Which type of current is used in mains electricity A) Alternating Current (AC). B) Direct Current (DC). C) All the above. D) None of the above. Show Answer Correct Answer: A) Alternating Current (AC). 20. What does the Root Mean Square (RMS) value represent in AC? A) The peak value of current. B) The average value of current. C) The effective value of AC. D) The instantaneous value of AC. Show Answer Correct Answer: C) The effective value of AC. 21. Which of the following is true about an inductor? I. It stores energy after the current stops flowing II. It opposes the change of current III. It can produce a magnetic field A) I. B) III. C) I and II. D) II and III. E) All of the above. Show Answer Correct Answer: D) II and III. 22. What type of electricity is used in our houses? A) Direct Currents. B) Alternating Currents. C) All the above. D) None of the above. Show Answer Correct Answer: B) Alternating Currents. 23. A 120 volt ac source is connected across a pure inductor of inductance 0.70 henry. If the frequency of the source is 60 Hz, the current passing through the inductor is ..... A) 4.55 amps. B) 0.355 amps. C) 0.455 amps. D) 3.55 amps. Show Answer Correct Answer: C) 0.455 amps. 24. What does RMS means? A) Really Monday Stinks. B) Root Minus Square. C) Root Mean Square. D) Root Minus Subtraction. Show Answer Correct Answer: C) Root Mean Square. 25. A 44 mH inductor is connected to a 220 V, 50 Hz ac supply. Determine the rms value of the current in the circuit. A) 1.38 A. B) 4.40 A. C) 15.9 A. D) 50.0 A. Show Answer Correct Answer: C) 15.9 A. ← 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 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 10Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 11 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books