ANS:D - all (a), (b) and (c)

The thickness of the condensate layer in filmwise condensation depends on all of the factors mentioned: (a) condensation rate, (b) surface configuration, and (c) liquid flow rate from the surface. Explanation:

• Condensation rate: The rate at which vapor condenses onto a surface affects the thickness of the condensate layer. Higher condensation rates result in thicker condensate layers, as more vapor is being converted into liquid.
• Surface configuration: The physical characteristics of the condensing surface, such as roughness, texture, and geometry, influence the thickness of the condensate layer. A smooth surface typically promotes thinner condensate layers compared to a rough or textured surface, as it provides less resistance to liquid flow and allows for better drainage.
• Liquid flow rate from the surface: The rate at which the condensed liquid flows away from the condensing surface affects the thickness of the condensate layer. Faster liquid flow rates promote thinner condensate layers, as they help remove the condensed liquid more efficiently, preventing buildup on the surface.