Calculate the force required to separate the glass plate of area of `10cm^(2)` with a film of water 0.05 mm. (Surface tension of water is `70xx10^(-3)N//m`)

Options

A. 14 N
B. 28 N
C. 56 N
D. 72 N

Answer

B

Explanation

`A=10^(-2)m^(2)x=0.05xx10^(-3)`
`therefore` Force required to separate the plates.
`F=(2TA)/(x)`
`=(2xx70xx10^(-3)xx10^(-2))/(0.05xx10^(-3))`
`=28N`