The correct option is D None of these
When a thin cylindrical shell is subjected to an internal pressure, then will be a increase in diameter and length of the shell.
Longitudinal strain,
εl=pd4tE(1−2μ)
Hoop strain,
εh=pd4tE(2−μ)
Volumetric strain,
εv=2εh+εl
=pd4tE(5−4μ)
We know,
μ≱0.5
So,
εl→+ve and εh→+ve
i.e., length and diameter both will increase.