Correct Answer - Option 2 : half

__Explanation:__

A thin pressure vessel having closed ends and contains a fluid under a gauge pressure ‘p’. Then the walls of the cylinder will have a longitudinal stress as well as a circumferential stress.

Circumferential or hoop stress: \({\sigma _h} = \frac{{pd}}{{2t}}\)

Longitudinal or axial stress: \({\sigma _L} = \frac{{pd}}{{4t}}\)

where ‘d’ is the internal diameter and ‘t’ is the wall thickness of the cylinder.

The ratio of longitudinal stress to hoop stress \( = \frac{{\frac{{pd}}{{4t}}}}{{\frac{{pd}}{{2t}}}} = \frac{2}{4} = 0.5\)