This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 38 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 38 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. If the inductance of an inductor is halved, how does its inductive reactance change at a constant frequency? A) It halves. B) It remains the same. C) It quadruples. D) It doubles. Show Answer Correct Answer: A) It halves. 2. What is one of the main advantages of alternating current (AC) over direct current (DC) in power transmission? A) AC can be easily stored in batteries. B) AC can be transmitted over long distances with lower energy losses. C) AC is safer than DC for all applications. D) AC is cheaper to produce than DC. Show Answer Correct Answer: B) AC can be transmitted over long distances with lower energy losses. 3. Each of three equal capacitors in series has ..... A) One-third the applied voltage. B) The original value of the applied voltage. C) Twice the applied voltage. D) Three times the applied voltage. Show Answer Correct Answer: A) One-third the applied voltage. 4. What does resonant frequency mean? A) The frequency at which the capacitive reactance and inductive reactance cancel out. B) The frequency at which capacitance and inductance are equal. C) The frequency at which a sine wave appears more like a straight line. D) None of the above. Show Answer Correct Answer: A) The frequency at which the capacitive reactance and inductive reactance cancel out. 5. A bulb of resistance 10 Ohm and a capacitor of capacitance 800 uF are connected in series to a source of alternating voltage V = 200 sin 300t. Calculate the impedance of the circuit A) 4.17 Ohm. B) 10.8 Ohm. C) 18.5 Ohm. D) 10.0 Ohm. Show Answer Correct Answer: B) 10.8 Ohm. 6. What is meant by the peak voltage in an alternating voltage? A) The maximum voltage reached. B) The minimum voltage reached. C) The voltage at zero crossing. D) The average voltage over a cycle. Show Answer Correct Answer: A) The maximum voltage reached. 7. What is the purpose of using a step-up transformer in power stations? A) To increase voltage for long-distance transmission. B) To decrease voltage for local distribution. C) To stabilise voltage fluctuations. D) To convert a.c. to d.c. Show Answer Correct Answer: A) To increase voltage for long-distance transmission. 8. Which of the following statement is TRUE concerning the impedance of an RCL circuit? A) The impedance is dominated by C at high frequencies. B) The impedance is dominated by L at high frequencies. C) The impedance depends only on the value R. D) The impedance depends only on the value C and L only. Show Answer Correct Answer: B) The impedance is dominated by L at high frequencies. 9. The value of inductive reactance is A) 0.1 $\Omega$. B) 62.8 $\Omega$. C) 14 $\Omega$. D) 31.4. Show Answer Correct Answer: D) 31.4. 10. The root mean square of the alternating current is equal to A) Twice the peak value. B) Half the peak value. C) $\frac{1}{\sqrt[]{2}}$. D) Equal to peak value. Show Answer Correct Answer: C) $\frac{1}{\sqrt[]{2}}$. 11. Which of the following statements CORRECTLY shows the effect on X$_{L}$ when f is increased to 2f? A) X$_{L}$ increases by a factor of two. B) X$_{L}$ decreases by a factor of two. C) X$_{L}$ increases by a factor of four. D) X$_{L}$ decreases by a factor of four. Show Answer Correct Answer: A) X$_{L}$ increases by a factor of two. 12. What is not the reason for the loss of power in the transformer A) Heat loss due to the resistance of the coils. B) Leakage of magnetic field lines between the primary and secondary coils. C) Heat loss due to eddy currents induced in the iron core. D) Heat loss due to radiation of electromagnetic waves. E) Heat loss due to repeated magnetization and demagnetization of the core. Show Answer Correct Answer: D) Heat loss due to radiation of electromagnetic waves. 13. What is the term for a current that reverses its direction periodically? A) Direct Current (DC). B) Alternating Current (AC). C) Static Current. D) Pulsating Current. Show Answer Correct Answer: B) Alternating Current (AC). 14. Phase angle is the ..... A) Total phase between current and voltage in DC circuit. B) Phase difference between current and voltage in DC circuit. C) Total phase between current and voltage in AC circuit. D) Phase difference between current and voltage in AC circuit. Show Answer Correct Answer: D) Phase difference between current and voltage in AC circuit. 15. The opposition to current flow offered by an inductor in an AC circuit is A) Inductance. B) Capacitive Reactance. C) Inductive Reactance. D) None of the above. Show Answer Correct Answer: C) Inductive Reactance. 16. What happens to the current in an R.L.C circuit at resonance? A) The current reaches its maximum value. B) The current fluctuates wildly. C) The current is halved. D) The current is zero. Show Answer Correct Answer: A) The current reaches its maximum value. 17. Fill in the blank:The overall length of course of treatment is usually longer than the ..... A) Blend. B) Dose. C) Interval. D) Session. Show Answer Correct Answer: A) Blend. 18. What does the term 'smoothing' refer to in the context of rectification? A) Increasing the peak voltage. B) Decreasing the frequency of the output. C) Making the voltage output more stable. D) Reducing the current through the load. Show Answer Correct Answer: C) Making the voltage output more stable. 19. What words are missing from the following statement? The impedance of a series RCL circuit at resonance will be ..... and equal to the circuit ..... A) Minimum and resistance. B) Maximum and resistance. C) Minimum and reactance. D) Maximum and reactance. Show Answer Correct Answer: A) Minimum and resistance. 20. In an LCR circuit capacitance is changed from C to 2 C. For the resonant frequency to remain unchanged, the inductance should be changed from L to A) 4/L. B) 2 L. C) L/2. D) L/4. Show Answer Correct Answer: C) L/2. 21. An AC source produces emf E=E$^\circ$ sin wt. The rms value depends directly on: A) Frequency only. B) Peak value only. C) Angular frequency only. D) Time period only. Show Answer Correct Answer: B) Peak value only. 22. What does electromotive force (emf) represent? A) A type of electrical resistance. B) An electrical action produced by a non-electrical source. C) The speed of a conductor. D) The strength of a magnetic field. Show Answer Correct Answer: B) An electrical action produced by a non-electrical source. 23. ..... is a representation of how alternating current varies with time. A) WAVEFORM. B) VOLTAGE. C) CURRENT. D) None of the above. Show Answer Correct Answer: A) WAVEFORM. 24. Current from a battery is A) AC. B) DC. C) BC. D) AC/DC. Show Answer Correct Answer: B) DC. 25. If the frequency of A.C is large, the reactance of capacitor is A) Large. B) Small. C) Zero. D) None. Show Answer Correct Answer: B) Small. ← 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