If the stress on a wire is 10\(^7\)Nm\(^{-2}\) and the wire is stretched from its...

JAMB 1999

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

A. 5 . 0 x 10⁴ Nm^-2
B. 5 . 0 x 10⁵ Nm^-2
C. 2 . 0 x 10⁸ Nm^-2
D. 2 . 0 x 10⁹ Nm^-2

WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

Your School's Whatsapp Group - Join Us now

Correct Answer: Option D

Explanation

Y = \(\frac{\text{stress}}{\text{strain}}\), but stress = 10\(^7\)Nm\(^{-2}\) (given).

Strain = \(\frac{\text{e}}{l_o}\). = \(\frac{(0.1005 - 0.100)}{0.1}\) = 0.005m

Thus Y = \(\frac{10^7}{0.005}\) = 2.0 x 10\(^9\)Nm\(^{-2}\)

(NOTE: cm → m)

Previous Next

Go back to Phy classroom

Report an Error Ask A Question Download App