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

 

Please read this first: http://forum.allaboutcircuits.com/showthread.php?t=3002