This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 14 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 14 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What happens if the live wire touches the metal case of an appliance? A) The appliance will work normally. B) The appliance will become live and dangerous. C) The appliance will stop working. D) The appliance will become insulated. Show Answer Correct Answer: B) The appliance will become live and dangerous. 2. An alternating voltage is described by $V=240\sin400t$ $V$ A) 240 V. B) 250 V. C) 170 V. D) 340 V. Show Answer Correct Answer: C) 170 V. 3. What is the formula to calculate the RMS voltage from the peak voltage? A) Vrms = Vmax x 0.5. B) Vrms = Vmax x 0.707. C) Vrms = Vmax x 1.414. D) Vrms = Vmax x 2. Show Answer Correct Answer: B) Vrms = Vmax x 0.707. 4. Based on the phasor diagram of RL circuit. The rms supply voltage V (or total voltage) of the circuit is given by A) The sum of all voltage in the circuit. B) The sum of the squares of voltage across R and L. C) The square root of the sum of the squares of the voltage across R and L,. D) The square root of the sum of all voltage in the circuit. Show Answer Correct Answer: C) The square root of the sum of the squares of the voltage across R and L,. 5. Opening the secondary circuit of a current transformer under load will cause a dangerous level of ..... A) Induced high voltage. B) Induced high current. C) High impedance. D) Low impedance. Show Answer Correct Answer: A) Induced high voltage. 6. What is the voltage level for heavy industry supply in the UK? A) 33kV or 11kV. B) 50kV or 25kV. C) 66kV or 33kV. D) 100kV or 50kV. Show Answer Correct Answer: A) 33kV or 11kV. 7. The frequency of an alternating current is A) The speed with which the alternator runs. B) The number of cycles generated in one minute. C) The number of waves passing through a point in one second. D) The number of electrons passing through a point in one second. Show Answer Correct Answer: C) The number of waves passing through a point in one second. 8. When an AC voltage of 220 V is applied to the capacitor C A) The maximum voltage between plates is 220 V. B) The current is in phase with the applied voltage. C) Power delivered to the capacitor is zero. D) The charge on the plates is in phase with the applied voltage. Show Answer Correct Answer: C) Power delivered to the capacitor is zero. 9. Why use AC for electricity supply? A) All of the above. B) It can be transformed to high voltages. C) It has lower power losses in transmission lines. D) It can work equally well with DC. Show Answer Correct Answer: A) All of the above. 10. As the number of turns in the coil increases, what happens to the inductance of the coil? A) Becomes zero. B) Remains the same. C) Decreases. D) Increases. Show Answer Correct Answer: D) Increases. 11. A bulb is connected first with dc and then ac of same voltage then it will shine brightly with A) A.c. B) D.c. C) Brightness will be in ratio 1/(1.4). D) Equally with both. Show Answer Correct Answer: D) Equally with both. 12. In an RC, RL or RCL circuit, the total opposition to alternating current is called as A) Reactant. B) Impedence. C) Phase angle. D) Resistance. Show Answer Correct Answer: B) Impedence. 13. Complete the sentence:The ..... wire is connected to the longest pin in a plug. A) Live. B) Neutral. C) Earth. D) None. Show Answer Correct Answer: C) Earth. 14. When an alternating current passes through a conductor then the direction of A) Current remains constant. B) Voltage remains constant. C) Both the current and voltage changes. D) Current remains constant but direction of voltage changes. Show Answer Correct Answer: C) Both the current and voltage changes. 15. Which of the following is a commonly used term related to alternating current? A) Direct voltage. B) Frequency. C) Static electricity. D) Resistance. Show Answer Correct Answer: B) Frequency. 16. The instantaneous current in an ac circuit is I = 2.0 sin 314 twhat is rms value of the current? A) 1.414 A. B) 1 A. C) 2 A. D) 1 / 1.414 A. Show Answer Correct Answer: A) 1.414 A. 17. What is the primary function of a diode bridge in an AC circuit? A) To store energy. B) To allow current to flow in one direction. C) To increase the voltage. D) To convert AC to DC. Show Answer Correct Answer: D) To convert AC to DC. 18. The opposition to AC current flow presented by capacitors and inductors taken together is called: A) Resistance. B) Reactance. C) Impedance. D) Reluctance. Show Answer Correct Answer: B) Reactance. 19. The value of output voltage in the secondary coil is A) 1.2 V. B) 3 V. C) 12 V. D) 6 V. Show Answer Correct Answer: A) 1.2 V. 20. The type of current where charges shake back and forth in a circuit A) Alternating Current. B) Direct Current. C) Voltage. D) Switchback Current. Show Answer Correct Answer: A) Alternating Current. 21. Most office and domestic equipment such as TVs, audio systems, amplifiers, flash lights, computers, tablets and smartphones use A) AC power. B) DC power. C) All the above. D) None of the above. Show Answer Correct Answer: A) AC power. 22. What does RC stand for? A) Remote Control. B) Radio Control. C) Resistor Capacitor. D) Rotary Club. Show Answer Correct Answer: C) Resistor Capacitor. 23. How is phase difference measured? A) Phase difference is measured in hertz. B) Phase difference is measured in meters. C) Phase difference is measured in volts. D) Phase difference is measured in degrees or radians. Show Answer Correct Answer: D) Phase difference is measured in degrees or radians. 24. What is the frequency of alternating current in the UK? A) 50 Hertz. B) 230 volts. C) Not mentioned. D) Cannot be determined. Show Answer Correct Answer: A) 50 Hertz. 25. The opposing force that an inductor presents to the flow of alternating current is called ..... A) Inductive reactance. B) Inductive resistance. C) Resistance. D) Anti-current. Show Answer Correct Answer: A) Inductive reactance. ← 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