Q. How much force is required to produce an increase of 0.2% in the length of a brass wire of diameter $0.6\ mm$ (Young’s modulus for brass $= 0.9 \times 10^{11}N/m^{2}$)
A) Nearly $17\ N$
B) Nearly $34\ N$
C) Nearly $51\ N$
D) Nearly $68\ N$
Explanation
(c) $F = \frac{YAl}{L} = 0.9 \times 10^{11} \times \pi \times \left( 0.3 \times 10^{- 3} \right)^{2} \times \frac{0.2}{100} = 51\ N$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.