Question

Consider the following statements:
(A) Whentemperature increases, the viscosity of gases increases and viscosity of liquids decreases.
(B) Water does not wet an oily glass because the cohesive force of oil is less than that of water.
(C) A liquid will wet a surface if the angle of contact is greater than 90◦.
Which of the following is true?

• A. A, B and C are false
• B. A and B false, C is true
• C. B and C false, A is true
• D. A and C false, B is true

Hint:

For surface tension and wetting, angle of contact less than \( 90^\circ \) indicates wetting.

Answer 1

The Correct Option is C

% Option (A) True: Gas viscosity increases, liquid viscosity decreases with temperature.
% Option (B) False: Water does not wet oily surfaces due to lack of adhesion, not due to cohesion of oil.
% Option (C) False: Liquids wet solids when angle of contact is<\( 90^\circ \), not greater.