This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 6 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 6 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Which type of current goes back and forth in a circuit? 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). 2. What type of transformer is used to increase the voltage from 25kV to 275kV? A) Step-down transformer. B) Step-up transformer. C) Isolation transformer. D) Auto transformer. Show Answer Correct Answer: B) Step-up transformer. 3. If the peak current in an AC circuit is 3.0 A, what is the rms value of the current? A) 1.5 A. B) 2.12 A. C) 3.0 A. D) 4.24 A. Show Answer Correct Answer: A) 1.5 A. 4. AC is a result of A) Chemical reaction. B) Electromagnetic reaction. C) Biological reaction. D) None of the above. Show Answer Correct Answer: B) Electromagnetic reaction. 5. A sine wave has a Peak-to-Peak voltage of 88Volts, what is the RMS voltage of this sine wave? A) 88 Volts. B) 44 Volts. C) 31.1 Volts. D) 62.23 Volts. Show Answer Correct Answer: C) 31.1 Volts. 6. An alternating current is given by the equation $i=i_1\\cos\omega t+i_2\\sin\omega t$ A) $\frac{1}{\sqrt{2}}\left(i_1+i_2\right)$. B) $\frac{1}{\sqrt{2}}\left(i_1+i_2\right)^2$. C) $\frac{1}{\sqrt{2}}\left(i_1^2+i_2^2\right)^{\frac{1}{2}}$. D) $\sqrt{2}\left(i_1^2+i_2^2\right)^{\frac{1}{2}}$. Show Answer Correct Answer: C) $\frac{1}{\sqrt{2}}\left(i_1^2+i_2^2\right)^{\frac{1}{2}}$. 7. The opposition to current flow offered by the capacitance of a circuit is known as ..... A) Mutual inductance. B) Inductive reactance. C) Capacitive reactance. D) Pure resistance. Show Answer Correct Answer: C) Capacitive reactance. 8. Which type of current only flows in 1 direction around a circuit? A) Direct Current (DC). B) Alternating Current (AC). C) All the above. D) None of the above. Show Answer Correct Answer: A) Direct Current (DC). 9. Average Power transferred to the capacitor is A) 5W. B) Zero. C) 11W. D) 15W. Show Answer Correct Answer: B) Zero. 10. Which of the following conditions exists in a circuit of pure inductance? A) The voltage and current are 180$^\circ$ out of phase. B) The voltage and current are 90$^\circ$ out of phase. C) The voltage and current are 120$^\circ$ out of phase. D) The voltage and current are in phase. Show Answer Correct Answer: B) The voltage and current are 90$^\circ$ out of phase. 11. The power factor in a circuit connected to an ac A) Unity when the circuit contains an ideal inductance only. B) Unity when the circuit contains an ideal resistance only. C) Zero when the circuit contains an ideal resistance only. D) Unity when the circuit contains an ideal capacitance only. Show Answer Correct Answer: B) Unity when the circuit contains an ideal resistance only. 12. A technician needs to repair a faulty AC circuit in a home. What steps should they take to ensure safety before starting the repair? A) Leave the power on and use metal tools. B) Turn off the main power supply, use insulated tools, and wear protective gear. C) Work quickly to avoid danger. D) Use water to clean the area. Show Answer Correct Answer: B) Turn off the main power supply, use insulated tools, and wear protective gear. 13. What does the acronym ICE stand for? A) Energy Last Internal. B) Voltage Lags Current in Inductor Circuits. C) Current Leads Voltage in Capacitor Circuits. D) Voltage Leads Current in Capacitor Circuits. Show Answer Correct Answer: C) Current Leads Voltage in Capacitor Circuits. 14. A series LCR circuit is connected to a variable-frequency source with values:$V = 230$ $L = 5$ $C = 80$ $R = 40$ A) 5.00 Hz. B) 7.96 Hz. C) 8.84 Hz. D) 50.0 Hz. Show Answer Correct Answer: B) 7.96 Hz. 15. Using the phasor diagram of an LCR series circuit with $V_L > V_C$ A) Z = $\sqrt{R^2 + (X_L-X_C)^2}$. B) Z = R + X L + X C. C) Z = $\sqrt{X_L^2-X_C^2}$. D) Z = $\sqrt{R^2 + X_L^2 + X_C^2}$. Show Answer Correct Answer: A) Z = $\sqrt{R^2 + (X_L-X_C)^2}$. 16. A student wants to design a simple AC circuit for a lamp. Which components are essential for the circuit to work safely? A) Lamp, wire, battery. B) Lamp, wire, fuse, switch. C) Lamp, wire, solar cell. D) Lamp, wire, resistor. Show Answer Correct Answer: B) Lamp, wire, fuse, switch. 17. What is the phase relationship between voltage and current in a purely resistive AC circuit? A) Current leads voltage by 90 degrees. B) The phase relationship is that voltage and current are in phase. C) Voltage and current are 180 degrees out of phase. D) Voltage leads current by 90 degrees. Show Answer Correct Answer: B) The phase relationship is that voltage and current are in phase. 18. What does a High-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: A) Blocks low frequency signals. 19. What is the difference in frequency between the two currents? A) An Alternating Current has a frequency of 0hz, and a Direct Current usually has a frequency of 60hz. B) They both have a frequency of 60hz. C) An Alternating Current usually has a frequency of 60hz, and a Direct Current normally has a higher frequency. D) An Alternating Current usually has a frequency of 60hz, and a Direct Current has a frequency of 0hz. Show Answer Correct Answer: D) An Alternating Current usually has a frequency of 60hz, and a Direct Current has a frequency of 0hz. 20. In a pure inductor ac circuit A) Current lead voltage by 90'. B) Voltage lead current by 90'. C) Both current and voltage are in phase. D) Current and voltage are out of phase. Show Answer Correct Answer: B) Voltage lead current by 90'. 21. The value of current in the primary coil is A) 2 A. B) 0.2 A. C) 0.02 A. D) 0.4 A. Show Answer Correct Answer: C) 0.02 A. 22. UCLES N93/I/18. A sinusoidal alternating current of peak value I$_{o}$ passes through a heater of resistance R.What is the mean power output of the heater? A) $\frac{I_o^2R}{2}$. B) $\frac{I_o^2R}{\sqrt{2}}$. C) $I_o^2R$. D) $I_o^2R\sqrt{2}$. E) $2I_o^2R$. Show Answer Correct Answer: A) $\frac{I_o^2R}{2}$. 23. What is the relationship between frequency and capacitive reactance in an AC circuit? A) It is inversely proportional. B) It is directly proportional. C) It remains constant regardless of frequency. D) It is independent of the capacitance value. Show Answer Correct Answer: A) It is inversely proportional. 24. Which of the following coils is likely to show the lowest inductance? A) A coil with a short core. B) A coil with a magnetic core. C) A coil with many turns. D) A coil with a narrow diameter. Show Answer Correct Answer: D) A coil with a narrow diameter. 25. Alternating current can be represented by: A) Sine curve. B) Cos curve. C) Neither sine nor cos. D) Both sine and cos. Show Answer Correct Answer: D) Both sine and cos. ← 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 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