If the stress on a wire is 10\(^7\)Nm\(^{-2}\) and the wire is stretched from its original length of 10.00 cm to 10.05 cm. The Young's modulus of the wire is
5 . 0 x 104 Nm-2
5 . 0 x 105 Nm-2
2 . 0 x 108 Nm-2
2 . 0 x 109 Nm-2
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Error-original lenght/original lenght=strain(young modulus)
error=10.05
original length=10.00
10.05-10.00=0.5/10.00 which gives 0.005
THE YOUNG MODULUS OF THE WIRE:
NM^-2 =0.005
Nm^-2 =0.005/10^7
(^7 comes up) ie:0.0000000005/10 =2.0x10^9Nm-2
Y=stress/strain. By applying formular for percentage error, u get ur strain. Thus strain= error÷true measurement= 10.05-10.00÷10.00=0.05÷10=0.005. Back to our formula where Y=syress /strain, Y=100000000/0.05= 2×10^9Nm-2.
Y=stress/strain.
stress=10^7 N/M^2
strain=extension(e)/original lenght(lo)
extension=L2-L1=10.05-10=0.05
original lenght=10
strain=0.05/10=5*10^-3
YOUNG'S MODULUS=10^7/5*10^-3= 2*10^9
(use simple indices to calculate the last step)
the answer is wrong they didn't convert the centimeters to metre it is 2E-10nm2
Jennyryda am nt so sure of ur calculations, pls check it again and make it to be error free.
The answer they gave's solitarily correct,no arguments please.
Lest I forget,am Shedrach,a 2014/2015 aspirant of Fedponek into Science lab.tech. Nice meeting you guys.
pls I'm new here and I'm not really good at physics I'll really appreciate if anyone could tutor me here 
tnks
Strain = extension/original length, since both the numerator and denominator have the same unit there is no need for unit conversion here, just make sure your extension and original length have the same unit, be it in cm, mm, m or even km, it doesn't matter; it therefore means that strain has no unit.
The option chosen is incorrect due to the fact that the extension=10.05cm-10.00cm=0.05cm and not 0.005cm chosen in the question
