This is how VIVA exam of a ELECTRONIcs n
TELECOMMUNICATION
>engineering student of fourth semester of subject
ELECTRONIX-1 &
>2 went at a Mumbai University College :
>
>
>****************************************************
>
>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.
>
>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.
>
>Interviewer: How will you reverse direction of an
Induction
>motor?
>Candidate: I will remove the four bolts at the base,
turn the
>motor around, and put back the bolts.
>
>Interviewer: How do you start a synchronous motor?
>Candidate: Vrrrrrrrmmmmmmmmmmmmmmmmmmm (in rising
pitch)
>
>Interviewer: Stop! Stop!
>Candidate: rrrrrrrmmmmmmmmmmmmmmmmmmmm (in falling
pitch)
>
>Interviewer: How do you limit surge current within an
integrated
>circuit?
>Candidate: By using a miniature circuit breaker.
>
>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!"
>
>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
>basement 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!"