A thin cylinder of ‘D’ internal diameter, is subjected to an internal pressure of ‘P’. If the permissible tensile stress is σt, the cylinder wall thickness should be
1
\(\frac{2\sigma_t}{PD}\)
2
\(\frac{PD}{\sigma_t}\)
3
\(\frac{PD}{4\sigma_t}\)
4
\(\frac{PD}{2\sigma_t}\)