The surface tension of soap solution is $0.03\, N/m$. The work done in blowing to form a soap bubble of surface area $40 \, cm^2, (in\, J)$ is
- $ 1.2 \times 10^{-4} $
- $ 2.4 \times 10^{-4} $
- $ 12 \times 10^{-4} $
- $ 24 \times 10^{-4} $
The Correct Option is B
Solution and Explanation
$W = T \times 2 \times \Delta A$
$ = 0.03 \times 2 \times 40 \times 10^{-4}$
$ = 2.4 \times 10^{-4} \, J $
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Concepts Used:
Surface Tension
The amount of energy required to increase the liquid's surface area by one unit area is known as surface tension. In other words, it is a property of the liquid surface to resist force.
Surface tension is defined as,
The ratio of the surface force F to the length L along which the force acts.
Mathematically, the surface tension formula can be expressed as follows:
T=F/L
Where,
- F is the force per unit length
- L is the length in which force act
- T is the surface tension of the liquid
Read More: Detergents and Surface Tension
Factors affecting surface tension:
- Impurities: The surface tension decreases with the addition of impurities.
- Surfactants: Adding surfactants in liquids lowers the tension of water making it interrupt aside or get susceptible.
- Temperature: The surface tension of a liquid reduces as the temperature rises.
The Unit of Surface Tension:
The SI unit of Surface Tension is Newton per Meter or N/m.