Question

A liquid does not wet the solid surface if the angle of contact is then

• A. zero
• B. equal to ${45}^o$
• C. equal to ${90}^o$
• D. greater than ${90}^o$

Answer 1

Answer: (D)

greater than ${90}^o$

We know that the liquids make the solid substances wet when they get into physical contact with each other. This depends on the contact angle between the liquid and solid surfaces. When the liquid does not wet the sides of a solid object, it means that the angle of contact is more than $90°$ but less than $180°.$

A liquid does not wet the solid surface if the angle of contact is obtuse (i.e. $\theta >{90}^o$).