This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Physics Part I > Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction – Quiz 8 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 8 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What happens to the secondary coil in mutual induction? A) It generates heat. B) It becomes a magnet. C) It remains unaffected. D) It induces an alternating emf. Show Answer Correct Answer: D) It induces an alternating emf. 2. What do you notice about the direction of the current as the wire crosses the midpoint? A) The current stops completely. B) The current reverses direction. C) The current increases in magnitude. D) The current continues in the same direction. Show Answer Correct Answer: B) The current reverses direction. 3. What cause-and-effect statement best describes what happens in a generator? A) A changing magnetic field causes current to be produced in a wire. B) A current carrying wire causes a magnetic field to be produced around the wire. C) All the above. D) None of the above. Show Answer Correct Answer: A) A changing magnetic field causes current to be produced in a wire. 4. What is one way to increase the current in a wire? A) Decrease the number of coils. B) Increase the number of coils. C) Move the magnet slower. D) Take the wire off of the magnet. Show Answer Correct Answer: B) Increase the number of coils. 5. Transformers are used in the transmission of electrical power to houses. Which type of transformer is used at the power station prior to connection to the power lines and which type is used prior to delivery to the houses? A) Step-up, step-down. B) Step-down, step-down. C) Step-down, step-up. D) Step-up, step-up. Show Answer Correct Answer: A) Step-up, step-down. 6. What is necessary to generate a current in addition to a potential difference? A) The wire must be stationary. B) The ends of the wire must be connected to form a circuit. C) The magnetic field must be constant. D) The wire must be insulated. Show Answer Correct Answer: B) The ends of the wire must be connected to form a circuit. 7. An alternating current I in ampere varies with time t in second according to the equation I = 5 sin 314 t. What is the mean power developed by the current in a resistive load of 10W and frequency of a.c. supply? A) 125W, 50 Hz. B) 125W, 100 Hz. C) 250W, 50 Hz. D) 250W, 100 Hz. Show Answer Correct Answer: A) 125W, 50 Hz. 8. A current produced by an induced e.m.f. is called? A) Magnetic current. B) Current flow. C) Current. D) Induced current. Show Answer Correct Answer: D) Induced current. 9. You have a coil of wire. You take a bar magnet and pull its North pole away from the coil. According to Lenz's Law, the face of the coil closest to the magnet will ..... A) Become a North pole. B) Become a South pole. C) Become electrically positive. D) Not be affected. Show Answer Correct Answer: B) Become a South pole. 10. A circular loop of flexible conducting material is kept in a magnetic field directed perpendicularly into its plane.By holding the loop at diametrically opposite points its is suddenly stretched outwards, then A) No current is induced in the loop. B) Clockwise current is induced. C) Anti-clockwise current is induced. D) Only e.m.f. is induced. Show Answer Correct Answer: B) Clockwise current is induced. 11. In A.C generator, by increasing the no. of turns in the coil, A) Increases the Electromotive force (EMF). B) Electromotive force (EMF) remains the same. C) Electromotive force (EMF) becomes zero. D) Decrease the Electromotive force (EMF). Show Answer Correct Answer: A) Increases the Electromotive force (EMF). 12. Which rule is used to determine the direction of force when a current-carrying conductor is in the magnetic field. A) Fleming's left hand rule. B) Fleming's right hand rule. C) Right hand grips rule. D) Faraday's palm rule. Show Answer Correct Answer: A) Fleming's left hand rule. 13. Why is permanent magnet able to exert a force on an electric charge? A) Electric charges have a magnetic field. B) A permanent magnet has an electric field. C) Electric charges have an electric field. D) A permanent magnet cannot exert a force on an electric charge. Show Answer Correct Answer: A) Electric charges have a magnetic field. 14. The radius of a circular coil having 50 turns is 2 cm. Its plane is normal to the magnetic field. The magnetic field changes from 2T to 4T in 3.14 sec. The induced emf in coil will be:- A) 4 mV. B) 0.04V. C) 0.4V. D) 0.12 V. Show Answer Correct Answer: C) 0.4V. 15. A coil of wire is placed in a changing magnetic field. What is induced in the coil? A) A direct current (DC). B) An alternating current (AC). C) No current. D) None of the above. Show Answer Correct Answer: B) An alternating current (AC). 16. Magnetic Resonance Imaging (MRI) is an application of magnet. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 17. In which of the following situations is an e.m.f. induced in a conductor? A) The conductor is moved in a magnetic field. B) The conductor is connected to a battery. C) The conductor is connected to a motor. D) The conductor moves through the air. Show Answer Correct Answer: A) The conductor is moved in a magnetic field. 18. A 60 turn square coil of area 0.042 m$^{2}$ and a 40 turn circular coil are both placed perpendicular to the same magnetic field. The voltage induced in each of the coils is the same. What is the area of the circular coil? A) 0.034 m$^{2}$. B) 0.063 m$^{2}$. C) 0.028 m$^{2}$. D) 0.083 m$^{2}$. E) 0.075 m$^{2}$. Show Answer Correct Answer: B) 0.063 m$^{2}$. 19. The process of inducing an electric current with a magnetic field known as electromagnetic induction. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 20. In a 12 V transformer connected to a regular 120 V /5 A line. the output current will be A) 50 A. B) 20 A. C) 1.2 A. D) None of the above. Show Answer Correct Answer: A) 50 A. 21. What can electromagnets do that regular magnets can't? A) Explode. B) No difference, both are the same. C) Burn. D) Switch their magnetic fields. Show Answer Correct Answer: D) Switch their magnetic fields. 22. What is the purpose of the open circuit test in determining the equivalent circuit parameters of a transformer? A) To measure the magnetization current. B) To measure the copper losses. C) To measure the core losses. D) To measure the leakage flux. Show Answer Correct Answer: C) To measure the core losses. 23. Current is ..... through a wire. A) Protons moving. B) Electrons moving. C) Neutrons moving. D) Atoms moving. Show Answer Correct Answer: B) Electrons moving. 24. Transformer is device that A) Converts AC voltage to a different level at the same frequency. B) Converts electrical energy to kinetic energy. C) Converts AC voltage to a different level at the same amplitude. D) Converts AC voltage to current. Show Answer Correct Answer: A) Converts AC voltage to a different level at the same frequency. 25. What is the effect of electromagnetic induction in a conductor? A) Creates a magnetic field. B) Creates an electric field. C) Generates current. D) Generates voltage. E) Both C and D. Show Answer Correct Answer: E) Both C and D. 26. Solenoid #1 has a length L, cross-sectional area A, and N turns. Solenoid #2 has a length 2L, cross-sectional area 2A, and 2N turns. Which solenoid has the greater magnetic field at its center when equal currents are going through them? A) #1. B) #2. C) Both have the same magnetic field. D) Since it depends on the values of A and L, none of the above are correct. Show Answer Correct Answer: C) Both have the same magnetic field. 27. What is the purpose of the commutator in a d.c. electric motor? A) To control the speed at which the motor rotates. B) To reverse the direction of the voltage across the power supply every half-turn. C) To reverse the direction of the current in the motor coil every half-turn. D) To reverse the direction of spin of the motor coil every half-turn. Show Answer Correct Answer: C) To reverse the direction of the current in the motor coil every half-turn. 28. For a transformer to work properly, it must ..... A) Be connected to direct current. B) Have infinite resistance. C) Be connected to alternating current. D) Have a core made of Carbon. Show Answer Correct Answer: C) Be connected to alternating current. 29. Dynamos are generators that produce direct current. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 30. A solenoid wound over a rectangular frame. If all the linear dimensions of the frame are increased by a factor 3 and the number of turns per unit length remains the same, the self inductance increased by a factor of- A) 63. B) 3. C) 9. D) 227. Show Answer Correct Answer: C) 9. 31. Which of the following equations are correct for the magnitude of the electric field strength when the Hall Effect occurs? A) E = Bv. B) E = B/ v. C) E = v/B. D) None of the above. Show Answer Correct Answer: A) E = Bv. 32. Which of these is a valid form of Ohm's Law? A) $V=I^2\times R$. B) $V=I\times R$. C) $V=\frac{I}{R}$. D) $V=\frac{R}{I}$. Show Answer Correct Answer: B) $V=I\times R$. 33. What is the SI unit of magnetic flux? A) Tesla. B) Weber. C) Farad. D) Joule. E) Volt. Show Answer Correct Answer: B) Weber. 34. What will occur if two positively charged particle are placed near each other? A) Repulsion. B) Attraction. C) Depends on the magnet. D) Nothing. Show Answer Correct Answer: A) Repulsion. 35. Which of the following factors DOES NOT affect the self inductance of a coil? A) The current flows in the coil. B) The length of the coil. C) The number of turn of the coil. D) The cross sectional area of the coil. Show Answer Correct Answer: B) The length of the coil. 36. An inductor opposes any change in: A) Voltage. B) Frequency. C) Current. D) Reactance. Show Answer Correct Answer: C) Current. 37. According to Faraday's law, what induces an electromotive force (emf) in a coil? A) Fixed current. B) Constant magnetic field. C) Static electric field. D) Changing magnetic flux. Show Answer Correct Answer: D) Changing magnetic flux. 38. A coil and a magnet moves with their constant speeds 5 m/sec. and 3 m/sec. respectively, towards each other, then induced emf in coil is 16 mV. If both are moves in same direction, then induced emf in coil- A) 15 mV. B) 64 mV. C) Zero. D) 4 mV. Show Answer Correct Answer: C) Zero. 39. When was electromagnetism discovered? A) 2031. B) 1831. C) 1931. D) 1731. Show Answer Correct Answer: B) 1831. 40. "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. 41. 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) 11 $\mu H$. B) 13 $\mu H$. C) 9.6 $\mu H$. D) 7.5 $\mu H$. Show Answer Correct Answer: B) 13 $\mu H$. 42. 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. 43. 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. 44. Which of these crucial 19th-century inventions or discoveries came FIRST, providing the essential tool that made the others possible? A) The Galvanometer. B) The Battery (Voltaic Pile). C) The Electromagnet. D) The Law of Induction. Show Answer Correct Answer: B) The Battery (Voltaic Pile). 45. 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 unbalanced. B) It becomes equal. C) No effect. D) It becomes zero. Show Answer Correct Answer: D) It becomes zero. 46. 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. 47. Which of the following factors does not affect the inductance of a coil? A) The length of the coil. B) The cross-sectional area of the coil. C) The number of turns of the coil. D) The current flows in the coil. Show Answer Correct Answer: A) The length of the coil. 48. A step up transformer has its primary winding to secondary winding ratio A) Less than 1. B) Greater than 1. C) Unknown. D) Equal to 1. Show Answer Correct Answer: A) Less than 1. 49. 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 disappears. D) The wire loop changes color. Show Answer Correct Answer: A) The wire loop lights up. 50. 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. 51. "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. 52. 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. 53. 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. 54. 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) 0 volt. D) 2 volt. Show Answer Correct Answer: B) 4 volt. 55. 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) -4V. C) 8V. D) Zero. Show Answer Correct Answer: C) 8V. 56. 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) 18.84ohm. B) 18.72ohm. C) 18.82ohm. D) 18.62ohm. Show Answer Correct Answer: D) 18.62ohm. 57. When do we have self induction? A) When the coil moves into the magnet. B) When a changing current passes through the coil. C) When the magnet moves into the coil. D) When a constant current passes through the coil. Show Answer Correct Answer: B) When a changing current passes through the coil. 58. Which of the following does not use the application of eddy current? A) Electric power meters. B) LED lights. C) Induction furnace. D) Magnetic brakes in trains. Show Answer Correct Answer: B) LED lights. 59. 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) 83 turns. C) 54 turns. D) 1, 920 turns. Show Answer Correct Answer: B) 83 turns. 60. Describe a practical example of self-induction. A) A battery storing energy for later use. B) A capacitor discharging its stored energy. C) An example of self-induction is when an inductor in a circuit generates a back EMF when the current is suddenly interrupted. D) A transformer stepping up voltage in a circuit. Show Answer Correct Answer: C) An example of self-induction is when an inductor in a circuit generates a back EMF when the current is suddenly interrupted. ← PreviousNext →Related QuizzesScience QuizzesClass 12 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 9 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books