Homework help/:

Discussion in 'Homework Help' started by jacyhui, May 26, 2008.

  1. jacyhui

    Thread Starter New Member

    May 26, 2008
    1
    0
    MCQs:

    1. What is the disadvantage of using contact brushes in an a.c generator?
    a emf generated is very much reduced
    b heat oss through brushes very high
    c current drawn from the generator would be small
    d sparks will appear at the contact

    2. A step up transformer is used to...
    a low potential energy to high
    b low current to high
    c direct current to alternating
    d low to high power

    3. the primary coil of an ideal step up transformer is connected to a low dc source. what will appear at the secondary coil?
    a high potential energy
    b high potential a.c.
    c no power
    d low current a.c

    4. what is the material used to make the core of an ideal transformer?
    a aluminium
    b iron
    c copper
    d stainless steel

    5 what is true of an ideal step-down transformer?
    a the power of pri coil is teh same as power at sec coil
    b the power is higher the the pri coil
    c the power is higher at the sec coil
    d the power of the sec coil is not dependent on the power at the pri coil

    please help me):
    i missed out a few phy lessons because i was down with some flu.
    so if possible, do offer some explanations with the answer so i can understand:)
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
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