Acircular steel cylinder has an external diameter of 0.2 m and internal diameter of 0.05 m and is subjected to an internal pressure of 300 mn/m2. sketch the cylinder showing the distribution of both hoop ? h and radial stresses 'or, across its thickness.

Determine (a) the maximum thermal efficiency of reversible power cycles operating between a hot reservoir at 1000°c and a cold reservoir at 200°c and (b) the maximum cops for reversible refrigeration and heat pump cycies, respectively, between 28°c and 14°c.