Q1: Adhesives

ANS:D - none of these.

The correct statement regarding adhesives is: Adhesives can't cure instantaneously after application on a surface. Explanation:

1. Adhesives can't be used in the form of pressure-sensitive tapes: This statement is incorrect. Adhesives can indeed be used in the form of pressure-sensitive tapes. Pressure-sensitive adhesives (PSAs) are a type of adhesive that forms a bond when pressure is applied to join the adhesive with a substrate. Examples include masking tape, duct tape, and adhesive bandages.
2. Adhesives can't join two dissimilar metals: This statement is incorrect. Adhesives can join two dissimilar metals. Many adhesives are designed to bond various materials, including metals. The effectiveness of the bond depends on the adhesive's properties and the surface preparation of the metals.
3. Adhesives cure instantaneously after application on a surface: This statement is incorrect. Most adhesives do not cure instantaneously after application. Many adhesives require some curing time to reach their maximum strength and bond integrity. The curing time can vary depending on factors such as adhesive type, temperature, humidity, and substrate materials.