Properties Of Solids And Liquids Question 385

Question: The force required to separate two glass plates of area $ {{10}^{-2}}m^{2} $ with a film of water 0.05 mm thick between them, is (Surface tension of water is $ 70\times {{10}^{-3}} $ N/m)[KCET 2000; Pb. PET 2001: RPET 2002]

Options:

A) 28 N

B) 14 N

C) 50 N

D) 38 N

Show Answer

Answer:

Correct Answer: A

Solution:

Force required to separate the plates $ F=\frac{2TA}{t}=\frac{2\times 70\times {{10}^{-3}}\times {{10}^{-2}}}{0.05\times {{10}^{-3}}}=28N $



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