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Surface Tension — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsSurface Tension1 Mark
Question
Assertion : lt is better to wash the clothes in cold soap solution.
Reason : The surface tension of cold solution is more than the surface tension of hot solution.
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Answer

(e) The soap solution, has less surface tension as compared to ordinary water and its surface tension decreases further on heating. The hot soap solution can, therefore spread over large surface area and also it has more wetting power. It is on account of this property that hot soap solution can penetrate and clean the clothes better than the ordinary water.

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