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 $
