Question

A wire of cross section 4 mm² is stretched by 0.1 mm by a certain weight. How far (length) will be wire of same material and length but of area 8 mm² stretch under the action of same force

• A. 0.05 mm
• B. 0.10 mm
• C. 0.15 mm
• D. 0.20 mm (5) 0.25 mm

Answer 1

Answer: (A)

0.05 mm

Answer 2

$l = \frac { F L } { A Y }$∴ $l \propto \frac { 1 } { A }$ (F,L and Y are constant]

$\frac { l _ { 2 } } { l _ { 1 } } = \frac { A _ { 1 } } { A _ { 2 } } = \frac { 4 } { 8 } = \frac { 1 } { 2 }$