🔍 Key Concepts

• Reflex type gauge glass relies on light reflection and refraction to show liquid vs vapor areas • How color, clarity, and darkness of the liquid affect what you can see in the glass • Which liquids are easy vs hard to see using light-based contrast methods

💭 Think About

• Think about which liquid will give the best contrast between the glass area with liquid and the area with vapor or air when light hits it. • Ask yourself: is a reflex gauge better for clear/transparent liquids or very dark/opaque liquids? • Consider in which case a simple visual contrast from reflected light is enough, without needing to distinguish fine differences in color.

✅ Before You Answer

• Verify how a reflex gauge makes the liquid level visible (reflection vs refraction). • Check which choice describes a liquid where color/opacity might make it hard to see the level with this type of gauge. • Confirm which application most benefits from a gauge that emphasizes clear light/dark contrast, not subtle color differences.