Q. An iron bar of length L, cross-section A and Young’s modulus Y is pulled by a force F from both ends so as to produce an elongation $l.$ Which of the following statement is correct?
A) $l\ \propto Y$
B) $l\ \propto l/A$
C) $l$ $\propto A$
D) $l\ \propto l/L$
Explanation
(b) $Y = \frac{F}{A} \times \frac{L}{l}\ \ \ \ or\ \ l = \frac{FL}{AY}\ \ \ or\ l\ \ \propto 1/A$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.