+2 - Physics - Unit 4. Electromagnetic Induction

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+2 - Physics - Unit 4. Electromagnetic Induction

Prepared by P. ILAIYARAJA M. Sc. ,B. Ed. , PG ASST IN PHYSICS , GHSS, PANCHANATHIKKULAM EAST, NAGAI DT.   ; & www. Padasalai. Net


Questions and Answers
  • 1. 
    Electromagnetic induction is not used in
    • A. 

      Room heater

    • B. 

      AC generator

    • C. 

      Choke coil

    • D. 

      Transformer

  • 2. 
    A coil of area of cross section with 10 turns is in a plane which is pendendicular to an uniform magnetic field of The flux though the coil is
    • A. 

      1 Wb

    • B. 

      10 Wb

    • C. 

      100 Wb

    • D. 

      Zero

  • 3. 
    Lenz’s law is in accordance with the law of
    • A. 

      Conservation of energy

    • B. 

      Conservation of charges

    • C. 

      Conservation of momentum

    • D. 

      conservation of flux

  • 4. 
    The self−inductance of a straight conductor is
    • A. 

      Zero

    • B. 

      Infinity

    • C. 

      Very large

    • D. 

      Very small

  • 5. 
    The unit henry can also be written as
    • A. 

      (4)

    • B. 

      (2)

    • C. 

      (3)

    • D. 

      (1)

  • 6. 
    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 is
    • A. 

      0.3 H

    • B. 

      0.003 H

    • C. 

      30 H

    • D. 

      4.8 H

  • 7. 
    A DC of 5A produces the same heating effect as an AC of
    • A. 

      5A rms current

    • B. 

      5 A peak current

    • C. 

      50 A rms current

    • D. 

      None of these

  • 8. 
    Transformer works on
    • A. 

      AC only

    • B. 

      DC only

    • C. 

      Both AC and DC

    • D. 

      AC more effectively than DC

  • 9. 
    The part of the AC generator that passes the current from the coil to the external circuit is
    • A. 

      Brushes

    • B. 

      Split rings

    • C. 

      Field magnet

    • D. 

      Slip rings

  • 10. 
    In an AC circuit the applied emf e = Eo sin (ωt + π/2) leads the current I = Io sin (ωt – π/2) by
    • A. 

      π

    • B. 

      π/4

    • C. 

      π/2

    • D. 

      0

  • 11. 
    Which of the following cannot be stepped up in a transformer?
    • A. 

      Input power

    • B. 

      input current

    • C. 

      Input voltage

    • D. 

      All

  • 12. 
    The power loss is less in transmission lines when
    • A. 

      Voltage is more but current is less

    • B. 

      Voltage is less but current is more

    • C. 

      Both voltage and current are more

    • D. 

      Both voltage and current are less

  • 13. 
    Which of the following devices does not allow d.c. to pass through?
    • A. 

      Capacitor

    • B. 

      Resistor

    • C. 

      inductor

    • D. 

      All the above

  • 14. 
    In an ac circuit
    • A. 

      The average value of current is zero

    • B. 

      the average value of square of current is zero.

    • C. 

      The average power dissipation is zero.

    • D. 

      The rms current is 2 time of peak current.