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 3 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 6 Electromagnetic Induction Quiz 3 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. When the current in a solenoid changes uniformly from-12.0 mA to 18.0 mA in 15.0 ms, a back-e.m.f. is induced in the solenoid. If the self-inductance of the solenoid is 3.97 H, what is the value of the back e.m.f.? A) 7.94 V. B) 8.79 V. C) 8.50 V. D) 10.2 V. Show Answer Correct Answer: A) 7.94 V. 2. Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is not correct? A) Transmission lines can be made thinner. B) Lower current implies less power loss. C) It is easy to reduce the voltage at the receiving end using step-down transformers. D) For a given power level, there is a lower current. Show Answer Correct Answer: A) Transmission lines can be made thinner. 3. Describe a real-world application of Faraday's Law. A) Solar panels generate electricity by applying Faraday's Law directly to sunlight. B) Electric generators convert mechanical energy into electrical energy using Faraday's Law. C) Electric cars use Faraday's Law to charge their batteries while driving. D) Electric heaters convert electrical energy into thermal energy using Faraday's Law. Show Answer Correct Answer: B) Electric generators convert mechanical energy into electrical energy using Faraday's Law. 4. Which is the only type of current that will work with transformers? A) Direct current. B) Alternating current. C) Resistance. D) None of the above. Show Answer Correct Answer: B) Alternating current. 5. Calculate the magnetic flux density of a magnetic field at the 50 turns having the radius of 0.5 m and carrying a current of 5A. A) 3.12 x 10-12 T. B) 3.12 x 10-6 T. C) 3.12 x 10-4 T. D) 3.12 x 10-8 T. Show Answer Correct Answer: C) 3.12 x 10-4 T. 6. Observe:Move the wire loop down, towards the magnet. Is this motion of the loop equivalent to the magnet moving up or down? A) It depends on the speed of the loop. B) No. C) Only if the magnet is stationary. D) Yes. E) Only if the loop is stationary. Show Answer Correct Answer: D) Yes. 7. According to Lenz's law, the direction of the induced current is such that it opposes the change in ..... A) Magnetic flux. B) Temperature. C) Electric field. D) Velocity. Show Answer Correct Answer: A) Magnetic flux. 8. An electric current can produce a magnetic field. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 9. What benefit is gained by the addition of the iron core in an electromagnet? A) It makes a strong magnet weaker. B) It makes a weak magnet stronger. C) There is no benefit at all. D) It lets currents interact with each other. Show Answer Correct Answer: B) It makes a weak magnet stronger. 10. Predict:Do you think you can induce an electric current in the wire loop by moving or rotating the loop? A) Yes, because moving or rotating the loop changes the magnetic field through the loop. B) No, because the loop needs to be connected to a power source. C) Yes, but only if the loop is made of a magnetic material. D) No, because moving or rotating the loop does not affect the magnetic field. Show Answer Correct Answer: A) Yes, because moving or rotating the loop changes the magnetic field through the loop. 11. SI unit for self inductance, L is A) Henry(H). B) Weber(Wb). C) Farad (F). D) Tesla(T). Show Answer Correct Answer: A) Henry(H). 12. A charged particle is injected into a uniform magnetic field such that its velocity vector is perpendicular to the magnetic field vector. Ignoring the particle's weight, the particle will ..... : A) Follow a circular path. B) Follow a spiral path. C) Move along a parabolic path. D) Move in a straight line. E) Move along a waveform. Show Answer Correct Answer: A) Follow a circular path. 13. For an electromagnet (or motor) model, what is the cause and effect of the model? A) Cause:light turns oneffect:current is produced. B) Cause:a changing magnetic fieldeffect:current is produced. C) Cause:batteryeffect:magnetic field around the wire. D) Cause:magnetic field changeseffect:battery is produced. E) Cause:current in a wireeffect:a magnetic field is produced around the wire. Show Answer Correct Answer: E) Cause:current in a wireeffect:a magnetic field is produced around the wire. 14. Faraday's Law states that the induced emf is proportional to ..... A) The current. B) The cross sectional area of the coil. C) The rate of change in the flux of the coil. D) None of the above. Show Answer Correct Answer: C) The rate of change in the flux of the coil. 15. Lenz's Law of electromagnetic induction is about the conservation of A) Charges. B) Mass. C) Momentum. D) Energy. Show Answer Correct Answer: A) Charges. 16. Who discovered the phenomenon of electromagnetic induction? A) James Clerk Maxwell. B) Michael Faraday. C) Nikola Tesla. D) Thomas Edison. Show Answer Correct Answer: B) Michael Faraday. 17. What is the effect of increasing the number of turns in a coil on the induced voltage? A) No effect on the voltage. B) Decreases the voltage. C) Increases the voltage. D) Reverses the voltage direction. Show Answer Correct Answer: C) Increases the voltage. 18. 1 Henry is equivalent to A) V.s/A. B) Tesla/s. C) Weber.Tesla. D) Weber.A/s. Show Answer Correct Answer: A) V.s/A. 19. A coil and bulb are connected in series with a 5V AC source.When a soft iron core is inserted in the coil, the light emerging from the bulb is ..... A) Remains same. B) Increases. C) Decreases. D) Becomes off. Show Answer Correct Answer: C) Decreases. 20. Which statement is incorrect about alternating current? A) The r.m.s current $I_{rms}=\sqrt{2}I_o$ $I_o$. B) The root-mean-square (r.m.s.) of an alternating current is the value of the direct current, that dissipates heat energy at the same rate in a resistor. C) The heating effect is given by = $I_{rms}^2R$. D) The peak power is twice the mean power. Show Answer Correct Answer: A) The r.m.s current $I_{rms}=\sqrt{2}I_o$ $I_o$. 21. The direction of induced current is given by which law? A) Lenz's law. B) Faraday's law. C) Ohm's law. D) Coulomb's law. E) Ampere's law. Show Answer Correct Answer: A) Lenz's law. 22. Which device use the concept of mutual inductance? A) Wheatstone bridge. B) Transformer. C) Working coil galvanometer. D) DC generator. Show Answer Correct Answer: B) Transformer. 23. State Lenz's Law in the context of electromagnetic induction. A) The induced current in a circuit opposes the change in magnetic flux that produced it. B) The induced current in a circuit accelerates the change in magnetic flux that produced it. C) The induced current in a circuit follows the change in magnetic flux that produced it. D) Lenz's Law states that the induced current in a circuit is always zero. Show Answer Correct Answer: A) The induced current in a circuit opposes the change in magnetic flux that produced it. 24. How does the direction of induced current relate to Lenz's Law? A) The induced current flows in the same direction as the change in magnetic flux. B) The induced current flows in a direction that opposes the change in magnetic flux. C) The induced current has no relation to the change in magnetic flux. D) The induced current flows randomly without any specific direction. Show Answer Correct Answer: B) The induced current flows in a direction that opposes the change in magnetic flux. 25. Which best reflects Faraday's Law? $\nabla\times E=-\frac{\delta B}{\delta t}$ A) An electric field exerts a force on the poles of a magnet. B) A magnet near a wire creates a current. C) A current through a wire creates a magnetic field. D) A coil of wire creates a magnetic field. Show Answer Correct Answer: C) A current through a wire creates a magnetic field. 26. Why is magnetic induction important? A) Electromagnets are very versatile. B) Every electric motor uses induction. C) Because it's an easy way to produce electricity. D) All of the above. Show Answer Correct Answer: D) All of the above. 27. Electromagnetic induction is ..... A) The process in which electricity is produced by connecting wires to a battery. B) The process in which lightning strikes a building. C) The process in which a current produces a magnetic field. D) The process in which a changing magnetic field generates electricity. Show Answer Correct Answer: D) The process in which a changing magnetic field generates electricity. 28. Explain the difference between self-induction and mutual induction. A) Self-induction is the induction of EMF in the same coil due to its own changing current, while mutual induction is the induction of EMF in a nearby coil due to the changing current in another coil. B) Mutual induction involves the same coil affecting itself. C) Self-induction is the result of external magnetic fields. D) Self-induction occurs only in transformers. Show Answer Correct Answer: A) Self-induction is the induction of EMF in the same coil due to its own changing current, while mutual induction is the induction of EMF in a nearby coil due to the changing current in another coil. 29. Determine the inductance of the coil if a 5 V self-induction EMF occurs at a rate of change of current of 10 A / s. A) 0, 5 H. B) 2 H. C) 0, 2 H. D) 5 H. Show Answer Correct Answer: A) 0, 5 H. 30. A magnet is moved in and out of a coil of wire connected to a high-resistance voltmeter. If the number of coils doubles, the induced voltage A) Halves. B) Quadruples. C) Is the same. D) Doubles. Show Answer Correct Answer: D) Doubles. 31. A conducting ring encloses an area of 2.0 cm$^{2}$ and is perpendicular to a magnetic field of strength 5.0 mT. The direction of the magnetic field is reversed in a time 4.0 s. What is the average emf induced in the ring? A) 0.50$\mu$V. B) 0.25 $\mu$V. C) 0.40$\mu$V. D) 0. Show Answer Correct Answer: A) 0.50$\mu$V. 32. This equation represents which law? $E=-\frac{N\Delta\Phi}{\Delta t}$ A) Faraday's Law. B) Newton's Law. C) Lenz's Law. D) Tesla's Law. Show Answer Correct Answer: C) Lenz's Law. 33. What happens to the potential difference when the wire stops moving? A) The potential difference increases. B) The potential difference disappears. C) The potential difference doubles. D) The potential difference remains the same. Show Answer Correct Answer: B) The potential difference disappears. 34. A magnet is moved inside a coil wire connect to a golvanometer . The galvanometer needle deflects due to induced current .The induced current. is due the change of ..... A) Induction current. B) Magnatic field. C) E.M.F. D) Voltage. Show Answer Correct Answer: B) Magnatic field. 35. .Assertion:In the phenomenon of mutual induction, self-induction of each of the coils persists. Reason:Self-induction arises when strength of current in same coil changes. In mutual induction, current is changing in both the individual coils. A) C. B) D. C) B. D) A. Show Answer Correct Answer: C) B. 36. AC generators have A) 1 slip ring. B) 4 slip rings. C) 2 slip rings. D) 3 slip rings. Show Answer Correct Answer: C) 2 slip rings. 37. Passing an electric current around an iron object will temporarily make the object magnetic. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 38. Which law states that the induced e.m.f. and the current constantly oppose the source that produces them? A) Charle's. B) Lenz's. C) Faraday's. D) Coulomb's. Show Answer Correct Answer: B) Lenz's. 39. The correct expression for motional emf is A) $IlB$. B) $NIBA$. C) $Blv^2$. D) $Blv$. Show Answer Correct Answer: D) $Blv$. 40. Choose the best definition for magnetic flux. A) The direction of magnetic field lines. B) The amount of electric current flowing through a conductor. C) The strength of a magnetic field at a point. D) The total magnetic field passing through a given area. Show Answer Correct Answer: D) The total magnetic field passing through a given area. 41. Which of the following devices is most likely to contain an electromagnet? A) Flashlight. B) Refrigerator. C) Gas stove. D) Digital watch. Show Answer Correct Answer: B) Refrigerator. 42. What is the voltage drop (in volts) of a 10 $\Omega$ resistor with 2 A of current running through it? A) $20$. B) 20 Mathematical EquivalenceON. C) All the above. D) None of the above. Show Answer Correct Answer: A) $20$. 43. Lenz's law is a consequence of the law of conservation of A) Energy. B) Mass. C) Charge. D) Momentum. Show Answer Correct Answer: A) Energy. 44. What did Michael Faraday say about induced EMF? A) It is inversely proportional to the rate of change of magnetic flux. B) It is constant regardless of the magnetic flux. C) It is proportional to the rate of change of magnetic flux. D) It decreases with the increase of magnetic flux. Show Answer Correct Answer: C) It is proportional to the rate of change of magnetic flux. 45. A long, current carrying wire passes through a circular loop of wire. If the current is constant, what is the induced emf of the loop? A) Clockwise. B) Counter Clockwise. C) I = 0. D) None of the above. Show Answer Correct Answer: C) I = 0. 46. A wire loop is held completely still in a very strong magnetic field. Why is NO current induced in the loop? A) The field is too strong. B) The wire isn't magnetic. C) The magnetic flux is not changing. D) The resistance is too high. Show Answer Correct Answer: C) The magnetic flux is not changing. 47. Describe the structure of a transformer A) Made of two coils of wire wound round an iron core. B) Made of wire coiled around a magnet. C) Made of 10 wires that are wrapped around a magnet. D) None of the above. Show Answer Correct Answer: A) Made of two coils of wire wound round an iron core. 48. Describe the direction of current in an AC generator? A) The electric current flows in one direction. B) The flow of electric current is irreversible. C) The electric current flows is permanent. D) The electric current reverses direction regularly. Show Answer Correct Answer: D) The electric current reverses direction regularly. 49. A transformer is designed to step up 110 V to 1320 V. If there are 300 turns on the primary side, how many turns are on the secondary side? A) 484. B) 1200. C) 3600. D) 25. Show Answer Correct Answer: D) 25. 50. How does Lenz's Law relate to electromagnetic induction? A) It determines the magnitude of induced current. B) It measures the voltage across a coil. C) It calculates the resistance in a circuit. D) It states that the direction of induced current opposes the change in magnetic flux. Show Answer Correct Answer: D) It states that the direction of induced current opposes the change in magnetic flux. 51. What is step-up transformer? A) A step-up transformer decreases voltage while increasing current. B) A step-up transformer increases voltage while decreasing current. C) A step-up transformer maintains both voltage and current levels. D) A step-up transformer converts AC to DC voltage. Show Answer Correct Answer: B) A step-up transformer increases voltage while decreasing current. 52. What is electromagnetic induction? A) The process of charging a body. B) The process of rotating a coil of an electric motor. C) Producing induced current in a coil due to relative motion between a magnet and the coil. D) The process of generating magnetic field due to a current passing through a coil. Show Answer Correct Answer: B) The process of rotating a coil of an electric motor. 53. If the magnetic flux through the circuit through the circuit is increasing, then induced emf acts to ..... the magnetic flux A) Increase. B) Decrease. C) Zero. D) None of these. Show Answer Correct Answer: B) Decrease. 54. Which rule is applied to ascertain the orientation of the area vector for a current-carrying loop? A) The finger rule. B) The thumb rule. C) The right-hand rule. D) The left-hand rule. Show Answer Correct Answer: C) The right-hand rule. 55. A coil carries a current in a magnetic field. The coil experiences a turning effect.Which device uses this effect? A) A relay. B) An electromagnet. C) A transformer. D) A d.c. motor. Show Answer Correct Answer: D) A d.c. motor. 56. How does increasing the magnet's speed affect the current? A) The current increases. B) The current remains the same. C) The current decreases. D) The current fluctuates. Show Answer Correct Answer: A) The current increases. 57. A circular loop of radius 10cm is placed in a magnetic field of strength 0.8T such that the normal to the plane of the loop is perpendicular to the magnetic field lines. What is the magnetic flux through the loop? A) 0.025Wb. B) 8Wb. C) 80pi Wb. D) 0Wb. Show Answer Correct Answer: D) 0Wb. 58. Explain how induction is utilized in electric motors. A) Induction is used to generate heat in electric motors. B) Induction in electric motors is utilized to create torque through the interaction of induced currents and magnetic fields. C) Induction creates a vacuum that powers the motor. D) Induction relies solely on mechanical friction to operate. Show Answer Correct Answer: B) Induction in electric motors is utilized to create torque through the interaction of induced currents and magnetic fields. 59. What is the cause of electromagnetic induction? A) Changing electric field. B) Constant magnetic field. C) Changing magnetic field. D) Constant electric field. E) Both A and C. Show Answer Correct Answer: C) Changing magnetic field. 60. Which of these is literally one of the best scientists of all time? A) Michael Faraday, FRS. B) Lucius Tarquinius Priscus. C) Dr. Hugh Janus, PhD. D) Cpt. Kathryn Janeway. Show Answer Correct Answer: A) Michael Faraday, FRS. ← 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 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 9 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books