Question

In CGS system, the Young's modulus of a steel wire is $2 \times 10 ^ { 12 }$. To double the length of a wire of unit cross-section area, the force required is

• A. $4 \times 10 ^ { 6 }$dynes
• B. $2 \times 10 ^ { 12 }$dynes
• C. $2 \times 10 ^ { 12 }$newtons
• D. $2 \times 10 ^ { 8 }$dynes

Answer 1

Answer: (B)

$2 \times 10 ^ { 12 }$dynes

Answer 2

To double the length of wire, Stress = Young's modulus

∴

If A = 1 then F = 2 × 10¹² dyne