A) \[{{10}^{2}}\]dyne
B) \[{{10}^{4}}\] dyne
C) \[{{10}^{5}}\]dyne
D) \[{{10}^{6}}\]dyne
Correct Answer: C
Solution :
The shape of water layer between the two plates is shown in the figure. Thickness d of the film \[=0.12\text{ }mm\] \[=0.012\text{ }cm\] Radius R of the cylindrical face\[=\frac{d}{2}\] Pressure difference across the surface \[=\frac{T}{R}=\frac{2T}{d}\] Area of each plate wetted by water\[~=\text{ }A\] Force F required to separate the two plates is given by F = pressure difference \[\times \] area \[=\frac{2T}{d}A\] Putting the given values, we get \[F=\frac{2\times 75\times 8}{0.012}={{10}^{5}}\,\text{dynes}\]You need to login to perform this action.
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