Joke

Engineering Student in viva :

Examiner to Student: which type of electrical

transmission wire system is used for high voltage

transmission.

Student: 3 Phase.

Examiner: How many wires are needed? Student: 3 wires, one for each phase.

Examiner: Then, what is the fourth one in some

cases?

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.

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Student: The 4th is for the birds to sit.