12th Class Physics MCQs Preparation 2022 and Onwards (Unit: Electromagnetic Induction: Set-2 (22 MCQs)) for National MDCAT, ECAT, FPSC, PPSC, JOB Exam, Physics Lecturer, SSC, HSSC (F.Sc.), BS, MS Exams NTS, ETS ETc..



1. For inducing e.m.f. in a coil the basic requirement is that




... Answer is D. both B and C are true
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2. When a single-turn coil rotates in a uniform magnetic field, at uniform speed the induced e.m.f. will be




... Answer is A. Alternating
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3. Principle of dynamically induced e.m.f. is used in a




... Answer is C. Generator
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4. The flow of electric current produces a magnetic field was discovered in 1820 by

 Christian Orsted
 


... Answer is A. Christian Orsted
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5.  Changing the magnetic field can also produce a current in a nearby circuit. this effect was studied by




... Answer is C. Both A and B
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6. The great discovery by Michal Faraday through his fundamental law has brought a revolution in the field of science and technology is:




... Answer is B. Law of electromagnetic induction
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7. The induced e.m.f produced depends upon the following factors :




... Answer is B. All of these
 Lenz's law not only provided the direction of the induced current it also gives the principle of law of conservation of Energy 


8. When the velocity of the rod is perpendicular to the applied magnetic field then the value of motion e.m.f. is




... Answer is B. Maximum
Ɛ = Bl sinθ and sin 90 = 1


9. Lenz's law not only provided the direction of the induced current it also gives the principle of:




... Answer is C. Law of conservation energy
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10. The unit of inductance is




... Answer is C. Henry
1 H = Wb A⁻¹ = V s A⁻¹ = kg m² s⁻² A⁻² [Wb= Weber, A=Ampere, V=Volt]


11. In a coil current changes from 2 to 4 A in 0.05 s. If the average induced e.m.f. is 8 V then the coefficient of self-inductance is




... Answer is A. 0.2 henry
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12. Which of the following, quantities remain constant in step-up transformer?




... Answer is C. power
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13. Step-up transformer has a transformation ratio of 3:2. What is the voltage in secondary, if voltage in the primary is 30V?




... Answer is A. 45 V
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14.  Eddy current is produced when




... Answer is A. a metal is kept in a varying magnetic field
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15. The changing current in one coil induces as e.m.f. in another nearby coil then such phenomena is known as




... Answer is C. Mutual induction
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16.. One Henry (1 H) is equal to




... Answer is D. All of these
1 H = Wb A⁻¹ = V s A⁻¹ = kg m² s⁻² A⁻² [Wb= Weber, A=Ampere, V=Volt]


17. A transformer works when we apply :




... Answer is A. A.C. voltage
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18. The working principle of an A.C. Generator is




... Answer is C. Induced Motional e.m.f.
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19. The soft iron core is used in a transformer in order to




... Answer is A. Enhance the magnetic flux
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20. In the transformer the power loss that occurs during magnetization and demagnetization of the iron core in each cycle of the AC is known as




... Answer is B. Hysteresis Loss
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21. When a step-up transformer delivers high voltage then the current will be




... Answer is B. Decreased
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22. For long-distance electrical power transmission, we use




... Answer is D. Smaller current and higher voltage
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