What is the expansion ratio of cryogenic helium?

The expansion ratio of cryogenic helium is a crucial concept to understand because it illustrates how a small volume of liquid helium can expand into a significantly larger volume of gas when it vaporizes. The correct answer, 750:1, indicates that one volume of liquid helium expands to 750 volumes of gas at standard temperature and pressure (STP).

This high expansion ratio plays an important role in applications such as cryogenics and in the functioning of superconducting magnets, where helium is often used as a coolant due to its low boiling point. When liquid helium is heated and transitions to the gaseous state, it occupies a much larger space, which must be managed carefully to avoid pressure buildup in closed systems.

The other expansion ratios provided do not accurately reflect the physical properties of helium. Understanding the correct ratio helps in effectively managing cryogenic systems and ensuring safety protocols are followed.