The lightest I-section for the same depth is
- AISMB
- BISLB
- CISJBCorrect
- DISWB
Solution
Concept
Indian standard I-sections
Step-by-step solution
1. Series by weight for the same depth: ISJB (junior) < ISLB (light) < ISMB (medium) < ISWB (wide).
Explanation
Junior beams have the lightest flange and web.
Why the other options are wrong
ISLB is light, ISMB is medium, and ISWB is wide flange (heavier).
Shortcut
J < L < M < W.
Common mistake
Choosing ISLB.
Correct answer: C) ISJB