This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 23 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 23 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Energy is measured by A) Watt.hr. B) Watt. C) Kilo Watt. D) Kilo Volt. Show Answer Correct Answer: A) Watt.hr. 2. A bridge rectifier requires at least ..... diode(s). A) 1. B) 2. C) 4. D) 8. Show Answer Correct Answer: C) 4. 3. Which of the following can act as an inductor? I. A long coil II. A long wireIII. A conducting sphere A) I. B) III. C) I and II. D) II and III. E) All of the above. Show Answer Correct Answer: A) I. 4. The phase difference between instantaneous voltage and current of purely capacitive circuit is A) 180. B) 90. C) 0. D) 360. Show Answer Correct Answer: B) 90. 5. A 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) $\frac{I_o^2R}{2}$. 6. The sum of resistance and reactance is referred to as ..... A) Geometric resistance. B) Conductance. C) Impedance. D) Susceptance. Show Answer Correct Answer: C) Impedance. 7. A bicycle generator creates 3 V, when bicycle is travelling with a speed of 9.0 km/h, the emf generated. The emf will be, when travelling with 15 km/h A) 5.0 V. B) 0 V. C) 10 V. D) 20 V. Show Answer Correct Answer: A) 5.0 V. 8. What is the destructive force of alternating current in beauty therapy? A) It creates thermal heat by friction, agitating molecules and causing them to vibrate. B) It cools the skin tissues. C) It increases blood flow. D) It reduces tissue swelling. Show Answer Correct Answer: A) It creates thermal heat by friction, agitating molecules and causing them to vibrate. 9. A power factor is not an angular measure, but a numerical ratio with a value between 0 and 1, equal to the ..... A) Tangent of the phase angle. B) Sine of the phase angle. C) Cotangent of the phase angle. D) Cosine of the phase angle. Show Answer Correct Answer: D) Cosine of the phase angle. 10. In LCR circuit, the capacitance is changed from C to 4C. For the same resonant frequency, the inductance should be changed from L to ..... A) 2L. B) L / 2. C) L / 4. D) 4L. Show Answer Correct Answer: C) L / 4. 11. Which of the following electrical devices is NOT used for controlling current and voltage in an alternating current (AC) circuit? A) Resistor. B) Inductor. C) Capacitor. D) Transistor. Show Answer Correct Answer: D) Transistor. 12. Coagulation converts liquid into solid through heating the tissues, breaking down the proteins within the molecules of the tissues to congeal or set. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 13. An A.C source is connected to a resistive circuit. Which of the following is true? A) Current leads the voltage and both are in same phase. B) Current lags behind the voltage and both are in same phase. C) Current and voltage are in same phase. D) Any of the above may be true depending upon the value of resistance. Show Answer Correct Answer: C) Current and voltage are in same phase. 14. Power Consumed by an Inductor in a half cycle is A) Imax x Vmax /2. B) Irms x Vrms / 2. C) Irms x Vrms. D) Zero. Show Answer Correct Answer: C) Irms x Vrms. 15. If a household appliance is rated at 220V AC, what does this mean? A) It operates only on DC voltage. B) It requires 220 volts of alternating current to function. C) It can operate at any voltage. D) It uses 220 volts of direct current. Show Answer Correct Answer: B) It requires 220 volts of alternating current to function. 16. Which of the following is a characteristic of a single-phase AC system? A) It has a constant power output. B) It is more efficient for large motors. C) It is typically used in residential homes. D) It requires three conductors. Show Answer Correct Answer: C) It is typically used in residential homes. 17. What is the peak voltage in an AC circuit? A) The peak voltage is the maximum voltage in an AC circuit. B) The peak voltage is the voltage at the midpoint of the AC waveform. C) The peak voltage is the average voltage in an AC circuit. D) The peak voltage is the minimum voltage in an AC circuit. Show Answer Correct Answer: A) The peak voltage is the maximum voltage in an AC circuit. 18. AC power is transmitted from a power house at high voltage as A) The rate of transmission is faster at high voltages. B) It is more economical due to less power loss. C) Power cannot be transmitted at low voltages. D) A precaution against theft of transmission lines. Show Answer Correct Answer: B) It is more economical due to less power loss. 19. An ac voltage $V = V_{m} \sin \omega t$ $C$ A) $i = I_{m} \sin (\omega t + \pi/2)$. B) $i = I_{m} \sin (\omega t-\pi/2)$. C) $i = I_{m} \sin \omega t$. D) $i = I_{m}\cos \omega t$. Show Answer Correct Answer: A) $i = I_{m} \sin (\omega t + \pi/2)$. 20. What does the acronym ELI stand for A) Energy Last Internal. B) Voltage Lags Current in Inductor Circuits. C) Voltage Leads Current in Inductor Circuits. D) Voltage Leads Current in Capacitor Circuits. Show Answer Correct Answer: C) Voltage Leads Current in Inductor Circuits. 21. Root mean square of ac current is the A) Average current. B) Instantaneous value of current. C) Value of dc that dissipates same power as ac through a resistor. D) Value of dc that dissipates same heat as ac through a resistor. Show Answer Correct Answer: C) Value of dc that dissipates same power as ac through a resistor. 22. What is the purpose of a transformer in an AC circuit? A) To change the voltage level of AC current. B) To store electrical energy in a circuit. C) To increase the frequency of AC current. D) To convert AC to DC current. Show Answer Correct Answer: A) To change the voltage level of AC current. 23. A transformer steps up 220 V to2200 V. What is the transformation ratio? A) 20. B) 0.1. C) 0.2. D) 10. Show Answer Correct Answer: D) 10. 24. Transformation ratio of a step-up transformer is A) Greater than one. B) Less than one. C) Equal to one. D) None of these. Show Answer Correct Answer: A) Greater than one. 25. The primary of a step-down transformer used for ringing door bell has 2000 turns of fine wire and the secondary has 100 turns .The transformer when connected at a potential difference of A) 5.5 V. B) 11V. C) 55 V. D) 220V. Show Answer Correct Answer: B) 11V. ← 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