🔍 Key Concepts

• pressure measurement devices commonly used in engine and boiler systems • difference between a device that uses a curved elastic tube versus one that uses a U-shaped liquid column • how a liquid level difference can represent pressure

💭 Think About

• Look at the shape of the tube shown. Is it straight, curved into a C-shape, or clearly U-shaped, and how does that relate to the way it senses pressure? • Ask yourself which option measures pressure by bending metal, and which one measures pressure by comparing the heights of a liquid column in two legs. • Consider whether this device is meant to float in a liquid to find density, or to stay fixed and show pressure as a height difference.

✅ Before You Answer

• Identify whether the illustration shows a U-shaped tube partially filled with water or a coiled/curved metal tube. • Check if the scale is reading height difference of a fluid column rather than psi or bar on a circular dial. • Eliminate any choices that are used primarily for measuring density or specific gravity, not pressure difference.