JAMB - Physics (1999 - No. 8)
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
Explanation
Y = \(\frac{\text{stress}}{\text{strain}}\), but stress = 10\(^7\)Nm\(^{-2}\) (given).
Strain = \(\frac{\text{e}}{l_o}\). = \(\frac{(10.05 - 10.00)}{10.00}\) = 0.005
Thus Y = \(\frac{10^7}{0.005}\) = 2.0 x 10\(^9\)Nm\(^{-2}\)
Strain = \(\frac{\text{e}}{l_o}\). = \(\frac{(10.05 - 10.00)}{10.00}\) = 0.005
Thus Y = \(\frac{10^7}{0.005}\) = 2.0 x 10\(^9\)Nm\(^{-2}\)
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