This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 3 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 3 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Describe the relationship between voltage and current in an AC circuit. A) Impedance has no effect on the relationship between voltage and current. B) Voltage and current in an AC circuit are related through impedance, and they can be out of phase. C) Voltage and current are always in phase in an AC circuit. D) Current is independent of voltage in an AC circuit. Show Answer Correct Answer: B) Voltage and current in an AC circuit are related through impedance, and they can be out of phase. 2. Universally available power is A) (a)AC power. B) (b)DC power. C) All the above. D) None of the above. Show Answer Correct Answer: A) (a)AC power. 3. What occurs when the conductor is moved at an angle of 45$^\circ$ to the magnetic field lines? A) Emf is generated at a moderate level. B) Emf is generated at a minimum level. C) Maximum positive emf is generated. D) No emf is generated. Show Answer Correct Answer: A) Emf is generated at a moderate level. 4. In a coil of self inductance 5 H the rate of change of current is 2 As$^{-1}$. Than emf induced in the coil is A) 10 V. B) -10 V. C) 5 V. D) -5 V. Show Answer Correct Answer: B) -10 V. 5. An inductor of reactance 1 $\Omega$ and a resistor of 2 $\Omega$ are connected in series to the terminals of a 6 V (rms) AC source. The power dissipated in the circuit is A) 8 W. B) 12 W. C) 14.4 W. D) 0 W. Show Answer Correct Answer: C) 14.4 W. 6. Reactance of a capacitor of capacitance C$\mu$F for ac frequency $\frac{400}{\pi}$ A) $50\\mu F$. B) $25\\mu F$. C) $100\\mu F$. D) $75\\mu F$. Show Answer Correct Answer: A) $50\\mu F$. 7. What is the primary function of the stator in an AC generator? A) To rotate and produce a magnetic field. B) To provide a stationary magnetic field. C) To convert mechanical energy to electrical energy. D) To store electrical energy. Show Answer Correct Answer: B) To provide a stationary magnetic field. 8. How does the turns ratio affect the voltage in a transformer? A) The turns ratio has no effect on the voltage. B) The turns ratio directly affects the voltage by determining whether the transformer steps up or steps down the voltage. C) The turns ratio only affects the current, not the voltage. D) The turns ratio determines the frequency of the voltage output. Show Answer Correct Answer: B) The turns ratio directly affects the voltage by determining whether the transformer steps up or steps down the voltage. 9. In an AC circuit, what does the term 'phase' refer to? A) The speed of the current. B) The position of the waveform relative to time zero or another waveform. C) The amount of current flowing. D) The type of load connected. Show Answer Correct Answer: B) The position of the waveform relative to time zero or another waveform. 10. When an AC voltage is applied to an LCR circuit, then A) I and V are out of phase with each other in R. B) I and V are in phase in L with in C, they are out of phase. C) I and V are out of phase in both C and L. D) I and V are out of phase in L and in phase in C. Show Answer Correct Answer: C) I and V are out of phase in both C and L. 11. Transformers in which the primary and secondary voltages are 180 degrees out of phase are known as ..... A) Unlike-wound transformers. B) Like-wound transformers. C) Unequal transformers. D) Step-up transformers. Show Answer Correct Answer: A) Unlike-wound transformers. 12. What is the phase relationship between the current and voltage in a purely capacitive circuit? A) The current leads the voltage by 90$^\circ$. B) The current lags the voltage by 90$^\circ$. C) The current leads the voltage by 0$^\circ$. D) None of the above. Show Answer Correct Answer: A) The current leads the voltage by 90$^\circ$. 13. What is the primary use of a step-up transformer in an X-ray tube? A) To convert AC to DC. B) To stabilize current. C) To increase voltage. D) To decrease voltage. Show Answer Correct Answer: C) To increase voltage. 14. Radio receivers are also known as A) R-C circuits. B) R-L circuits. C) L-C circuits. D) R-L-C circuits. Show Answer Correct Answer: A) R-C circuits. 15. Find the maximum value of current when inductance of 2 H is connected to 300V, 50 Hz supply A) 0.337 V. B) 0.676 V. C) 1.512 V. D) 2.224 V. Show Answer Correct Answer: B) 0.676 V. 16. Why is it important to reduce current in power transmission lines? A) To increase the speed of electricity flow. B) To reduce energy losses due to resistance. C) To make the lines safer for birds. D) To allow for more electricity to be transmitted. Show Answer Correct Answer: B) To reduce energy losses due to resistance. 17. When the potential difference(V) is divided by resistance(R) then what we will get? (V/R=?) A) Phase. B) Ampere (A). C) Q/T (Where Q=Charge & T=Time). D) Volt. Show Answer Correct Answer: C) Q/T (Where Q=Charge & T=Time). 18. Quantity of charge can be measured in A) Time (s). B) Ampere (A). C) Coulombs (C). D) Joule (J). Show Answer Correct Answer: C) Coulombs (C). 19. What is the maximum value of current or voltage in a waveform called? A) Wavelength. B) Period. C) Amplitude. D) Frequency. Show Answer Correct Answer: C) Amplitude. 20. If an electric bulb is connected to an AC source, which of the following statement is true about the phase difference between the voltage across the bulb and current flowing in it? A) In phase. B) Not in phase. C) The voltage is leading the current. D) The current is leading the voltage. Show Answer Correct Answer: A) In phase. 21. What is alternating current (AC)? A) Direct current (DC) flows in one direction only. B) Alternating current (AC) is a type of battery. C) Alternating current (AC) is always constant and unchanging. D) Alternating current (AC) is an electric current that periodically reverses direction. Show Answer Correct Answer: D) Alternating current (AC) is an electric current that periodically reverses direction. 22. The current produced by AC generators is A) Alternative current. B) Fixed current. C) Negative current. D) Direct current. Show Answer Correct Answer: A) Alternative current. 23. In a pure capacitive circuit if the frequency of ac source is doubled, then its capacitive reactance will be A) Remains same. B) Doubled. C) Halved. D) Zero. Show Answer Correct Answer: C) Halved. 24. In order for a circuit to work you need to have A) A voltage source. B) A complete pathway with no breaks in the circuit. C) A resistor. D) A voltage source and a complete pathway with no breaks in the circuit. Show Answer Correct Answer: D) A voltage source and a complete pathway with no breaks in the circuit. 25. What is the primary purpose of the simulation mentioned in the text? A) To explain the concept of resistance. B) To illustrate the properties of direct current. C) To show how alternating current EMF is produced. D) To demonstrate the heating effect of current. Show Answer Correct Answer: C) To show how alternating current EMF is produced. ← 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 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 10Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 11 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books