Correct Answer - Option 3 : dyne cm
-1
The correct answer is option 3) i.e. dyne cm-1
CONCEPT:
-
Surface tension is the tendency of water molecules to adhere to each other so as to form the minimum surface area possible.
-
This is a result of cohesion between water molecules.
- Towards the interface of water with air, there will be no cohesive forces. Hence the net force acts downwards.
- The top surface of the water will now act like a stretched membrane.
Surface tension (T) acting on a surface is given by:
\(T =\frac{F}{L}\)
Where F is the surface force and L is the length along which this force acts.
EXPLANATION:
-
Surface tension is mathematically defined as the force per unit length.
- The cgs unit of force is dyne and that of length is centimetre (cm)
- Hence, the cgs unit of surface tension is dyne cm-1.