28/03/2020Electromagnetic Induction(Senior Class Physics Study by Topics) 0Comments by Gate Academy Welcome to your Electromagnetic Induction(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. The current in the primary coil of a transformer is 2.5A. If the coil has 50 turns and secondary 250 turns, calculate the current in the secondary coil. (Neglect energy loss in the transformer)0.5 A0.2A2.5 A5.0 A2. Two inductors of inductances 5mH and 15mH are connected in series and a current of 5A flows through them. The total energy stored in the inductor is62.5 J500.0 J50.0 J250.0 J3. Since more magnetic field lines cross the area that is near the pole of a magnet, what does this indicate about the magnetic field strength in that location?It is leaving the magnetIt is entering the magnet.It is weaker.It is stronger.4. A coil of area of cross section with 10 turns is in a plane which is perpendicular to an uniform magnetic field of The flux though the coil is1 Wb100 WbZero10 Wb5. When there is an EMF, the direction of the current will always be such that (the magnetic field caused by it) will try to oppose the change producing it. Whose law is this?Maxwell's LawLenz's LawFaraday's LawBoltzmann's Law6. To convert alternating current dynamo into a direct current dynamo, thenumber of the turns in the coil is increasedstrength of the field magnet is increasedslip rings are replaced with a split ring commutator7. The core of an efficient transformer should consist of laminated pieces of metal in order toincrease the heat produced by reducing the eddy currentincrease the heat produced by increasing the eddy currentreduce the heat produced by increasing the eddy currentreduce the heat produced by reducing the eddy current8. A coil of 2H AND 10Ω resistance is connected to a 20V dc supply. Calculate the initial rate at which the current rises10 A/sec15 A/sec20 A/sec25 A/sec9. Which of the following devices may be used to step up the voltage in a dc circuit?a dc generatora wattmetera step up transformeran induction coil10. The part of the AC generator that passes the current from the coil to the external circuit isBrushesSplit ringsField magnetSlip rings11. What precaution should a manufacturer take to ensure that energy loss in a transformer is minimized?the core should be made of thin sheets of metalno magnetic material should be used to make the corethe flux linking the primary with the secondary coils should be minimumthe winding of the transformer should be made of high resistance wires12. A transformer has primary coil with 500 turns and a secondary coil with 2500 turns. When the voltage input to the primary coil is 120 V, the output is600 V60 V6000 V240 V13. A primary winding of a transformer has 400 turns and its secondary has 100 turns. If a source of emf for 12 V is applied to the primary, the secondary emf will be6 V3 V48 V24 V14. The unit henry can also be written as(2)(4)(3)(1)15. Which of the following is not directly associated with direct currenta lead acid accumulatora transformera moving coil galvanometera dry cell16. Carbon particles are used in carbon microphones becausetheir resistance changes with pressurethey amplify the soundthey are good conductorstheir resistance changes with temperature17. Power is transmitted at high voltages because the corresponding current in the wires isAlso high to deliver appreciable power to distant places.Low so that overheating of the wires is minimized.Choices A and B are both false.Choices A and B are both true.18. An emf of 12 V is induced when the current in the coil changes at the rate of. The coefficient of self induction of the coil is0.3 H4.8 H0.003 H30 H19. Which of the following cannot be stepped up in a transformer?Input currentInput voltageAllInput power20. Two separate inductors of 50 and 150 mH respectively are mounted so that the mutual inductance inductance between them is 40 mH.What will be the resulting inductance if they are connected in series opposing120 mH178 mH24 mH73 mH21. The metal detectors that people walk through at airports operate viaCoulomb's law.Newton's laws.Faraday's law.Ohm's law.22. In an AC circuit the applied emf e = Eo sin (ωt + π/2) leads the current I = Io sin (ωt – π/2) byπ/40π/2π23. A wire moving at right angles to a magnetic field has NO induced voltageIf it is moving very fast.If the wire is covered with insulation.None of the above choices are correct.If it is made of copper.24. The energy stored in an inductor of inductance 5mH when a current of 6A flows through it is 1¯−¹−²1.4 x 10-² J9.0 x 10-² J1.8 x 10-² J1.4 x 10-² J25. An magentic field points vertically upwards, a current carrying wire carries current to the left. In which way will the force be on the current carrying wire?UPTo LEFTAWAY from youTOWARDS you26 out of 25Time is Up!