Electromagnetic Induction
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Questions and Answers

What is the purpose of eddy currents induced in the aluminium frame of a moving coil galvanometer?

  • To improve the galvanometer's accuracy
  • To increase the coil's resistance
  • To enhance the sensitivity of the galvanometer
  • To damp the oscillation about the final steady position (correct)

    • What is the principle behind electric brakes?

  • Eddy currents opposing motion (correct)
  • Thermal braking
  • Frictional braking
  • Electromagnetic induction

    • Why is a solid core used in an induction furnace?

  • To increase the furnace's efficiency
  • To maximize heat generation (correct)
  • To reduce eddy currents
  • To minimize heat generation

    • What is the purpose of laminating the core in some applications?

    <p>To minimize eddy currents</p> Signup and view all the answers

    What type of galvanometer is characterized by the absence of oscillations?

    <p>Dead-beat galvanometer</p> Signup and view all the answers

    What is the direction of the magnetic field when the wheel rotates in a horizontal plane?

    <p>BV</p> Signup and view all the answers

    What is the net emf of the wheel in terms of the number of spokes N?

    <p>e net is independent of N</p> Signup and view all the answers

    What is the emf of a single metal spoke in the wheel?

    <p>e DYG</p> Signup and view all the answers

    What is the purpose of the conducting wheel in the given figure?

    <p>To convert mechanical energy into electrical energy</p> Signup and view all the answers

    What is the relationship between the angular velocity ω and the frequency ν of the wheel?

    <p>ω = 2πν</p> Signup and view all the answers

    What is the application of eddy currents in medical treatment?

    <p>Diathermy</p> Signup and view all the answers

    What is the principle behind the braking effect in energy meters?

    <p>Electromagnetic damping</p> Signup and view all the answers

    What is the purpose of the split ring commutators in a DC motor?

    <p>To reverse the current in the coil</p> Signup and view all the answers

    What is the effect of back emf on a DC motor?

    <p>It decreases the torque</p> Signup and view all the answers

    What is the type of coil used in a DC motor to reduce eddy current losses?

    <p>Laminated core coil</p> Signup and view all the answers

    What is the primary reason for using a laminated core design in some applications?

    <p>To reduce eddy current losses</p> Signup and view all the answers

    What is the principle behind electromagnetic damping in energy meters?

    <p>Lenz's law</p> Signup and view all the answers

    What is the purpose of dead-beat galvanometers?

    <p>To eliminate oscillations in measurements</p> Signup and view all the answers

    What is the application of eddy currents in electric brakes?

    <p>To convert kinetic energy into heat energy</p> Signup and view all the answers

    What is the effect of back emf on a DC motor?

    <p>It opposes the rotation of the motor</p> Signup and view all the answers

    What is the primary reason for using a light aluminium frame in a moving coil galvanometer?

    <p>To minimize eddy current losses</p> Signup and view all the answers

    What is the primary function of eddy currents in electric brakes?

    <p>To oppose the motion of the wheels and bring the train to a stop</p> Signup and view all the answers

    What is the advantage of using a laminated core in certain applications?

    <p>To minimize eddy current losses and heat generation</p> Signup and view all the answers

    What is the characteristic of a dead-beat galvanometer?

    <p>It has a critical damping, resulting in minimal oscillations</p> Signup and view all the answers

    In an induction furnace, what is the purpose of using a solid core?

    <p>To maximize heat generation and reduce the size of the furnace</p> Signup and view all the answers

    What is the primary purpose of laminating the core in some applications?

    <p>To reduce the energy losses due to eddy currents</p> Signup and view all the answers

    What is the characteristic feature of a dead-beat galvanometer?

    <p>It has an absence of oscillations</p> Signup and view all the answers

    What is the primary purpose of using a laminated core in an electric brake?

    <p>To reduce the energy losses due to eddy currents</p> Signup and view all the answers

    What is the principle behind the electromagnetic damping effect?

    <p>Eddy currents induce an opposing force on the wheel</p> Signup and view all the answers

    What is the primary purpose of using a copper disc in a Faraday copper disc generator?

    <p>To reduce the eddy current losses</p> Signup and view all the answers

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