UPSC Civil Service Exam Questions - Engineering

Q1:

A thin cylindrical shell of internal diameter D is subject to an internal pressure 'p'. If σy is the yield stress of the material of the cylinder, then based on the maximum shear theory, the thickness of the cylinder will be (in kg/cm2) is

A

B

C

D

ANS:A -

Can anyone please explain the answer? I thought the answer is option C.