Q. On increasing the length by 0.5 mm in a steel wire of length 2 m and area of cross-section 2 $mm^{2},\ $the force required is $\lbrack Y\ for\ steel = \ 2.2 \times 10^{11}Nm^{- 2}\rbrack$

A) $1.1\ \times 10^{5}N$
B) 1.1 $\times 10^{4}N$
C) 1.1 $\times 10^{3}\ N$
D) $1.1\ \times 10^{2}\ N$
Explanation

(d) $Y = \frac{Fl}{A\mathrm{\Delta}l}\ or\ \ F = \ \frac{YA\ \mathrm{\Delta}l}{l}$
Or $F = \ \frac{2.2 \times 10^{11} \times 2 \times 10^{- 6} \times 0.5 \times 10^{- 3}}{2}$
= $1.1\ \times 10^{2}N$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.