An angle of repose less than 25 degrees indicates what powder flow?

• A. Excellent
• B. Good
• C. Fair
• D. Poor

Answer: (A)

The angle of repose measures how freely a powder flows by looking at the slope of a cone that forms when the powder pours and comes to rest. A low angle means the particles slide past one another easily with little cohesion, so the pile is shallow and discharge is smooth. When the angle is less than 25 degrees, this indicates excellent flow, meaning the powder handles, discharges from hoppers, and fills processes with minimal sticking or bridging. As the angle increases, flowability decreases (higher angles reflect more cohesion and friction), which is why higher ranges are described as good, fair, or poor. So an angle below 25 degrees corresponds to excellent powder flow.