The change in length due to a tensile or compressive force acting on a body is given by (where P = Tensile or compressive force acting on the body, $$l$$ = Original length of the body, A = Cross-sectional area of the body and E = Young's modulus for the material of the body)

A. Single B. Double C. Both A and B D. None of these

A. Equal to B. Less than C. Greater than D. None of these

A. $$\frac{{{\text{w}}l}}{6}$$ B. $$\frac{{{\text{w}}l}}{3}$$ C. $${\text{w}}l$$ D. $$\frac{{2{\text{w}}l}}{3}$$

A. Short columns B. Long columns C. Weak columns D. Medium columns