In a structural steel work it is mentioned that a rolled steel section ISLB 500 @735.8 N/m was used in the work. This indicates that the section is
1
a T-section 500 mm deep and the self-weight is 735.8 N/m length
2
an I-section 500 mm deep and the self-weight is 735.8 N/m length
3
a T-section 500 mm deep, flange width 500 mm, and the self-weight is 735.8 N/m length
4
a channel section 500 mm deep and the self-weight is 735.8 N/m length