Q1: In order to know whether a column is long or short, we must know its slenderness ratio.

ANS:A - True

Depending upon slenderness ration column may be classified as a short column or long column.
IS: 456-2000 classifies a rectangular compression member as short when both the slenderness ratios (Lex/D) and (Ley/b) are less than 12. Where Lex = Effective length in respect of major axis Ley = Effective length in respect of minor axis D = Depth in respect of major axis b = width of member If any of these ratios is equal to more than 12, then it is termed as a slender or long column.

This definition is not suitable for non-rectangular and non-circular sections where the slenderness ratio is better defined in terms of the radius of gyration than the lateral dimensions.

Important Points For steel columns:
SR < 32 : Short column.
SR 32 - 120: Medium column.
SR > 120: Long Column.