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Curated by: Khan Academy India - English (28 videos)
In this video, we explore the concept of angle of contact, how liquid surfaces curve, and how adhesive and cohesive forces influence this behavior. With real-life examples like water on glass and mercury droplets, you’ll understand when the angle is acute or obtuse, and why it matters in surface tension physics. 0:00 – Introduction 0:06 – Why liquid surface curves 0:24 – Adhesive vs Cohesive forces 0:45 – Case 1: Adhesive, Cohesive Water on glass 1:22 – Case 2: Cohesive, Adhesive Mercury on glass 1:57 – What is Angle of Contact 2:26 – Measuring the angle θ 2:49 – Case: Acute angle 3:06 – Case: Obtuse angle 3:11 – Interfacial tensions explained 4:15 – Deriving the formula 5:03 – When is the angle acute or obtuse? 6:19 – Example: Water on glass acute angle 6:46 – Example: Mercury on glass obtuse angle 7:49 – Standard angle values 8:08 – Summary and goodbye 👋 Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by Chandan Ganotra