Question

A drop of oil of volume 10 ^-10 m3 spreads out on water to make a circular film radius 10^-1m what is the thickness of the film

Answer 1

The thickness of the film is = 3.183e-9m

Step-by-step explanation:

It will help us if we understand that the shape of the circular film can be approximated to be a cylinder. The height of this cylinder, or its thickness, in this case, will be very small.

Since we can approximate the shape of the drop of oil to be a cylinder, after it has spread out on the surface of the water, we can use the cylindrical geometric formulas to find out how thick the film is.

The volume of a cylinder =
`\pi r^2 h`

our radius is given as
`10^(-1)m = 0.1m`

the volume is
`10 ^(-10) m^3=1e-10m^3`

Remember that our task is to find the height of the cylinder. We can do this by making the height the subject of the formula.

`h = (Volume)/(\pi r^2) = \\\\(1e-10)/(\pi * 0.1^2) = 3.183e-9m`

Therefore, the thickness of the film is = 3.183e-9m