this happened to my friend in Fsc 1st year chemistry practical.
he didnt prepare practical copy and managed to get a ready made copy at the eleventh hour.

the viva went as follows.

examiner: copy aap nay hud bnai ha?
X: off course sir hud he bnai ha.
examiner: are u sure?
X: sir ap yaqeen karain main nay hud bnai ha.
examiner: phir to main aap ka viva nahi lay skta
X: kyun sir kia hoa?
examiner: yar ap itnay laiq ho k aap ka viva leni ki zarurat he nhi.
X: sir kyun mazaq kr rahay hain?
examiner : nahi bhai main mazaq nhi kr raha jo shaks first year main he 2nd year ki copy bana lay us ki qabliyet pay kyun kr shak kia ja skta ha.

aur guftgu kafi nahushgawar andaz main hatam hui. mera dost us waqt ko kosta raha jb us nay yeh shortcut ihtyar krnay ka faisla kia aur copy ko aik bar bhi dekhnay ki zahmat tk na ki.
lkin dilchasb bat yeh ha k result aya to wo 25 main say 11 marks lay kr pas tha