Large tanks with hemispherical heads on both ends can be identified as:

• A. Vacuum
• B. Low pressure
• C. High pressure
• D. Standard

Answer: (C)

The main idea is that the shape of a tank’s ends relates to how much internal pressure it is designed to handle. Hemispherical ends spread stress evenly across the surface, which makes the vessel better suited to contain high internal pressures without failing. That is why large tanks with hemispherical heads on both ends are characteristic of high‑pressure service. They’re built this way to withstand the demanding forces inside when the tank is pressurized. A vacuum vessel or a low‑pressure tank would use different end shapes and design features optimized for those conditions, and “standard” isn’t a designation used to describe pressure.