In a spherical dome the hoop stress due to a concentrated load at crown is A. Compressive everywhere B. Tensile everywhere C. Partly compressive and partly tensile D. Zero

The correct answer is: A. Compressive everywhere.

A spherical dome is a curved structure that is shaped like a sphere. The hoop stress is the stress that is perpendicular to the radius of the sphere. The hoop stress due to a concentrated load at the crown of the dome is compressive everywhere. This is because the load causes the dome to deform inward, which creates compressive stresses in the hoop direction.

The other options are incorrect because:

• Option B is incorrect because the hoop stress is compressive everywhere, not tensile everywhere.
• Option C is incorrect because the hoop stress is not partly compressive and partly tensile. It is compressive everywhere.
• Option D is incorrect because the hoop stress is not zero. It is compressive everywhere.