Quiz  /  Inductance Gate & PSU MCQ Questions With Answers

  • 1. 
    A bar magnet is falling through a loop of wire with constant velocity. The south pole enters first. As the magnet leaves the wire, the induced current (as viewed from above) is:

  • clockwise.
  • counterclockwise.
  • zero.
  • along the length of the magnet.

  • 2. 
    A sensitive ammeter is connected to a wire loop and placed within the magnetic field of a strong horseshoe magnet. The ammeter shows a deflection when:

  • the wire is moved parallel to the field.
  • the wire is moved perpendicularly to the field.
  • neither wire nor magnet is moving.
  • the wire's axis is parallel to the field.

  • 3. 
    A straight wire of length is oriented east-west and is in a magnetic field B pointing north. The wire is moving downward at a constant speed v. Which end of the rod is positively charged?

  • neither
  • the east end
  • the west end
  • both ends

  • 4. 
    In order to induce a voltage across a coil ____.

  • The coil must be in motion
  • Current must be increasing
  • There must be relative motion between the coil and the magnetic field
  • The coil must be cut by at least 10^8 lines of force per second

  • 5. 
    Rate of change in magnetic flux is

  • proportional to induced emf
  • inversely proportional to induced current
  • equal to magnetic flux
  • directly proportional to wire

  • 6. 
    An e.m.f will be induced in a straight conductor if

  • the conductor is stationary across a constant magnetic flux.
  • a constant magnetic flux is placed parallel to the conductor.
  • the conductor cuts across a constant magnetic flux.
  • the conductor moves parallel to a constant magnetic flux.

  • 7. 
    A coil in a magnetic field encloses a flux of 0.256 Tm2 when the angle between the normal to the coil and the direction of the magnetic field is 70.0°. What flux would go through the coil if the angle were changed to 40.0°?

  • 0.332 T·m2
  • 0.198 T·m2
  • 0.114 T·m2
  • 0.573 T·m2

  • 8. 
    1 Henry is equivalent to

  • Weber.Tesla
  • V.s/A
  • Tesla/s
  • Weber.A/s

  • 9. 
    The unit of inductance is:

  • volt
  • Ampere
  • Farad
  • Henry

  • 10. 
    Determine the factors which will not increases the induce emf of a coil

  • increasing the magnetic field.
  • increasing the cross sectional area of the coil
  • increasing the number of turns of the coil
  • decreasing the strength of magnetic field

  • 11. 
    An inductor go inductance 5mH, is connected in series with a 20 ohm resistor, the inductance time constant is

  • 2.5x10^-4 s
  • 4x10^4 s
  • 0.1s
  • 100s

  • 12. 
    According to Lenz’s law the direction of an induced current in a conductor will be that which tends to produce which of the following effects?

  • enhance the effect which produces it
  • produce a greater heating effect
  • produce the greatest voltage
  • oppose the effect which produces it

  • 13. 
    A uniform 4.5 T magnetic field passes perpendicularly through the plane of wire loop 0.10 m2 in area. What flux passes through the loop?

  • 5.00 Tm2
  • 0.450 Tm2
  • 0.250 Tm2
  • 0.135 Tm2

  • 14. 
    A 0.200-m wire is moved parallel to a 0.500-T magnetic field at a speed of 1.50 m/s. What emf is induced across the ends of the wire?

  • 2.25 V
  • 1.00 V
  • 0.600 V
  • zero

  • 15. 
    As the switch is closed, the lamp will

  • Glow instantly
  • Glow gradually
  • Glow then go dim
  • Never light up.

  • 16. 
    An inductor ____.

  • All of the above
  • Provides a specific value of inductance
  • Opposes any change in current
  • Stores energy in a magnetic field

  • 17. 
    Lenz’s Law of electromagnetic induction is about the conservation of

  • Energy.
  • Mass.
  • Charges.
  • Momentum

  • 18. 
    Which of the following is not the unit for magnetic field strength?

  • Tesla
  • Weber per meter squared
  • Weber per second squared
  • Gauss

  • 19. 
    A bar magnet is held above the center of a conducting ring in the horizontal plane. The magnet is dropped so it falls lengthwise toward the center of the ring. Will the falling magnet be attracted toward the ring or be repelled by the ring due to the magnetic interaction of the magnet and the ring?

  • It will be attracted.
  • It will be repelled.
  • It will be attracted only if the north end of the magnet is the leading end as it falls toward the ring.
  • It will be attracted only if the south end of the magnet is the leading end as it falls toward the ring.

  • 20. 
    After the switch is has been closed for a very long time, it is opened, what will the lamp do?

  • It glows
  • It doesn't glow
  • gradually goes dim
  • Dims then gradually glows

  • 21. 
    A metal rod is falling toward the surface of the Earth near the equator. As it falls, one end of the rod becomes positively charged due to the motional emf of the rod through the Earth's magnetic field. The rod is oriented so that:

  • the rod is vertical with the positive end higher.
  • the rod is horizontal with the positive end toward the north.
  • the rod is horizontal with the positive end toward the east.
  • the rod is horizontal with the positive end toward the west.

  • 22. 
    The magnetic field produced by a long straight current-carrying wire is

  • proportional to both the current in the wire and the distance from the wire.
  • proportional to the current in the wire and inversely proportional to the distance from the wire.
  • inversely proportional to the current in the wire and proportional to the distance from the wire.
  • inversely proportional to both the current in the wire and the distance from the wire.
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