Best answer by B.E students during viva

This is best answer by B.E students during viva.
This one is for those who had nightmares during their Engineering Viva's
(EEEs and ECEs). They bring back fond memories for those who care to
smile at the past..
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Interviewer: Why is a thicker conductor necessary to carry a current in
A.C.as compared to D.C. ?
Candidate: An AC current goes up and down (drawing a sinusoid) and
requires more space inside the wire, so the wire has to be thicker.
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External (to student ) : "Why does a capacitor block DC but allow AC To
pass through ?
Student: See, a capacitor is like this ---| |--- , OK. DC comes straight,
like this ---------- , and the capacitor stops it. But AC,goes UP, DOWN,
UP DOWN and jumps right over the capacitor!" .-------------------good
one :)
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Interviewer: How will you tell if that wall outlet carries AC or DC?
Candidate: I will put my finger in. If it is pushed away, it is AC. If it
gets stuck, it was DC.
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Interviewer: H! ow will you reverse direction of an Induction motor?
Candidate: I will remove the four bolts at the x-ud, turn the motor
around, and put back the bolts.
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Interviewer: How do you start a synchronous motor?
Candidate: Vrrrrrrrmmmmmmmmmmmmmmmmmmm (in rising pitch)
Interviewer: Stop! Stop!
Candidate: rrrrrrrmmmmmmmmmmmmmmmmmmmm (in falling pitch)
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Examiner: "What is a step-up transformer?"
Student: "A transformer that is put on top of electric poles."
Examiner (smiling): "And then what is a step-down transformer?"
Student (hesitantly):" Uh - A transformer that is put in the x-udment or
in a pit?"
Examiner (pouncing): "Then what do you call a transformer that is
installed on the ground?"
( Student knows he is caught-can't answer )
Examiner (impatiently): "Well?"
Student (triumphantly): "A stepless transformer, sir!"