Two shafts 'A' and 'B' are made of same material. The shaft 'A' is solid and has diameter D. The shaft 'B' is hollow with outer diameter D and inner diameter $$\frac{{\text{D}}}{2}$$. The strength of hollow shaft in torsion is _________ as that of solid shaft.

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