Topic: Fluid Mechanics
How does the viscosity of fluids vary with increase in temperature?
- A. Increases for both liquids and gases
- B. Increases for liquids, decreases for gases
- C. Increases for gases, decreases for liquids
- D. Decreases for both liquids and gases
Answer: C. Increases for gases, decreases for liquids
Explanation: For liquids, viscosity is predominantly due to cohesive forces, which decrease as temperature increases, causing viscosity to drop. For gases, viscosity is due to molecular momentum exchange (collisions), which increases with temperature, causing gas viscosity to increase.