Elastic section modulus is $Z=I/c$, where c is the distance from neutral axis to extreme fibre. Therefore $I/Z=c$. For the circular section, $c=d/2$, so the ratio is $d/2$, A. This avoids separately substituting the expressions for I and Z.
More Thin-walled pressure vessels questions
GATE 2026 ME Q51– A cylindrical pressure vessel made of steel has diameter of 3 m and wall thickness of 15…
GATE 2024 ME Q57– The figure shows a thin cylindrical pressure vessel constructed by welding plates together…
GATE 2023 ME Q40– The figure shows a thin-walled open-top cylindrical vessel of radius r and wall thickness…
GATE 2022 ME (ME1) Q52– A thin-walled cylindrical pressure vessel has mean wall thickness of t and nominal radius…
GATE 2018 ME (ME2) Q47– A thin-walled cylindrical can with rigid end caps has mean radius R = 100 mm and wall…
GATE 2016 ME (ME2) Q18– A thin cylindrical pressure vessel with closed-ends is subjected to internal pressure. The…