1. What is the average particle size of ultra-fine grinders? a) 1 to 20 µm b) 4 to 10 µm c) 5 to 200 µm d) 50 to 100 µm AnswerAnswer: a [Reason:] The particle averaging 1 to 2 µm in size with substantially all particles through a standard 325 mesh screen. 2. Which of…