• Cut-Off Diameter of Cyclone Separators:
• Lapple's Cut Diameter Equation ($d_{pc}$):

• Governing Factors:
• Inlet diameter / width ($W$): Determines the radial distance a particle must travel to strike the collector wall.
• Inlet air velocity ($v_i$): Generates the centrifugal vortex acceleration ($v_i^2 / r$).
• Effective number of turns ($N_e$): The number of helical gas revolutions inside the cyclone barrel and cone.
• (D) Pressure drop is a hydraulic consequence of gas flow rather than an independent parameter in the analytical cut-off equation.
• Conclusion: (A), (B) and (C) only (Option 2).

Correct option: (2) (A), (B) and (C) only,