Coast Guard Exams
Question 209Steam Plants - Assistant Engineer70% to pass

Bi-color water level indicators, connected directly to the boiler drum, operate on the principle of _______________.

AI Explanation
The correct answer is D) different refractive properties of steam and water. Bi-color water level indicators work on the principle of the different refractive properties of steam and water. Steam has a different refractive index compared to water, so the boundary between the two fluids is visually detectable. This allows the operator to easily monitor the water level in the boiler drum. The other answer choices do not accurately describe the operating principle of these water level indicators.