This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction – Quiz 20 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 20 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. "A current carrying coil placed in magnetic field experiences force", device that proves this law is A) DC generator. B) DC motor. C) AC generator. D) Both a and b. Show Answer Correct Answer: B) DC motor. 2. A solenoid of cross-sectional area 0.25 cm$^{2}$ and length 10 cm contains 200 turns of wire and the solenoid is air filled. Calculate the self-inductance L of the solenoid. A) 7.5 $\mu H$. B) 9.6 $\mu H$. C) 11 $\mu H$. D) 13 $\mu H$. Show Answer Correct Answer: D) 13 $\mu H$. 3. What is the purpose of the split-ring commutator in an electric motor? A) To ensure that the magnetic field in the motor changes direction every half rotation. B) To ensure that the magnetic field in the motor stays in the same direction at all times. C) To ensure that the turning effect on the motor changes direction every half rotation. D) To ensure that the turning effect on the motor stays in the same direction at all times. Show Answer Correct Answer: D) To ensure that the turning effect on the motor stays in the same direction at all times. 4. What is the main difference between electric charges and magnetic poles? A) Electric charges can be isolated, magnetic poles cannot be isolated. B) Electric charges cannot be isolated, magnetic poles can be isolated. C) Electric charges both attract and repel, magnetic poles only attract. D) Electric charges both attract and repel, magnetic poles only repel. Show Answer Correct Answer: A) Electric charges can be isolated, magnetic poles cannot be isolated. 5. Which of these crucial 19th-century inventions or discoveries came FIRST, providing the essential tool that made the others possible? A) The Electromagnet. B) The Galvanometer. C) The Law of Induction. D) The Battery (Voltaic Pile). Show Answer Correct Answer: D) The Battery (Voltaic Pile). 6. What happens to the magnetic flux of an object if the magnetic field line moves equally upon entry and exit in a closed area? A) It becomes equal. B) It becomes unbalanced. C) No effect. D) It becomes zero. Show Answer Correct Answer: D) It becomes zero. 7. If the magnetic flux through the circuit through the circuit is decreasing, then induced emf acts to ..... the magnetic flux. A) Increase. B) Decrease. C) Zero. D) None of these. Show Answer Correct Answer: A) Increase. 8. Which of the following factors does not affect the inductance of a coil? A) The number of turns of the coil. B) The current flows in the coil. C) The length of the coil. D) The cross-sectional area of the coil. Show Answer Correct Answer: C) The length of the coil. 9. A step up transformer has its primary winding to secondary winding ratio A) Greater than 1. B) Equal to 1. C) Less than 1. D) Unknown. Show Answer Correct Answer: C) Less than 1. 10. Observe:Drag the wire loop directly above the magnet. Click Forward and observe the wire loop and light bulb. As the magnet is moving, click the camera icon to take a snapshot. Right-click the image, and click Copy Image. Paste this image into a blank document. What do you notice in the wire? A) The wire loop lights up. B) The wire loop remains unchanged. C) The wire loop changes color. D) The wire loop disappears. Show Answer Correct Answer: A) The wire loop lights up. 11. According to the Lenz's law, if you pull the magnet away, then the induced current will A) Change the pull. B) Go with pull. C) Oppose the pull. D) Both a and b. Show Answer Correct Answer: C) Oppose the pull. 12. "The polarity of induced emf is such that it tends to produce a current which opposes the change in magnetic flux what produced it" given by A) Faraday law. B) Ampere circuital law. C) Biot savart law. D) Lenz's law. Show Answer Correct Answer: D) Lenz's law. 13. The Earth has a magnetic field. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 14. What does Faraday's Law of Induction state? A) A constant magnetic field generates an electric current. B) Electric current can create a magnetic field without any change. C) Magnetic fields do not affect electrical circuits at all. D) A change in magnetic flux induces an electromotive force in a circuit. Show Answer Correct Answer: D) A change in magnetic flux induces an electromotive force in a circuit. 15. A straight wire, 0.5 m long, is moved straight up at a speed of 20 m/s through a 0.4T magnetic field pointed in the horizontal direction.What EMF is induced in the wire? A) 8 volt. B) 4 volt. C) 2 volt. D) 0 volt. Show Answer Correct Answer: B) 4 volt. 16. A coil of self inductance 2H carries a 2A current. If direction of current is reversed in 1 sec., then induced emt in it- A) -8V. B) 8V. C) -4V. D) Zero. Show Answer Correct Answer: B) 8V. 17. An alternating EMF of 200V, 50Hz is applied to an LR circuit, having a resistance R of 10ohm. and inductance L of 0.05 Hz connected in series.calculate the impendence A) 18.72ohm. B) 18.62ohm. C) 18.82ohm. D) 18.84ohm. Show Answer Correct Answer: B) 18.62ohm. 18. When do we have self induction? A) When the magnet moves into the coil. B) When the coil moves into the magnet. C) When a constant current passes through the coil. D) When a changing current passes through the coil. Show Answer Correct Answer: D) When a changing current passes through the coil. 19. Which of the following does not use the application of eddy current? A) Electric power meters. B) Induction furnace. C) LED lights. D) Magnetic brakes in trains. Show Answer Correct Answer: C) LED lights. 20. A transformer with 240V AC input and 50V AC output, has 400 turns on its primary coil. How many turns are on the secondary coil? A) 4.8 turns. B) 54 turns. C) 83 turns. D) 1, 920 turns. Show Answer Correct Answer: C) 83 turns. 21. Describe a practical example of self-induction. A) A capacitor discharging its stored energy. B) An example of self-induction is when an inductor in a circuit generates a back EMF when the current is suddenly interrupted. C) A battery storing energy for later use. D) A transformer stepping up voltage in a circuit. Show Answer Correct Answer: B) An example of self-induction is when an inductor in a circuit generates a back EMF when the current is suddenly interrupted. 22. The coil has 500 turns. When the current is changed to 2 A, the magnetic flux through each turn changes by 4 mWb. Determine the inductance of the coil. A) 2 H. B) 0, 2 H. C) 1 H. D) 0, 1 H. Show Answer Correct Answer: C) 1 H. 23. What is the primary factor that affects the amount of induced emf in a coil? A) The speed of the coil's rotation. B) The temperature of the coil. C) The length of the coil. D) The color of the coil. Show Answer Correct Answer: A) The speed of the coil's rotation. 24. Changing current in a coil produces emf in the same coil. this phenomenon is known as A) Mutual induction. B) Self induction. C) Induced emf. D) Induced current. Show Answer Correct Answer: B) Self induction. 25. A(n) ..... converts electric energy into mechanical energy . A) Electric transformer. B) Electric generator. C) Electromagnet. D) Electric motor. Show Answer Correct Answer: D) Electric motor. ← PreviousNext →Related QuizzesClass 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 1Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 2Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 3Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 4Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 5Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 6Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 7Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 8Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 9Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 10 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books