A drop of volume 10^-10m^3 spreads out on a water to make a circular film of radius 10^-1m. What is the thickness of the film?

the volume of a cylinder is base * height. So, you have

v = πr^2 h
Now plug in your numbers for v and r, and find h.

To find the thickness of the film, we can use the formula:

Volume of the film = Area of the film x Thickness of the film

Given:
Volume of the drop = 10^-10 m^3
Radius of the film = 10^-1 m

First, let's find the area of the film:

Area of the film = πR^2
= π(10^-1)^2
= π(10^-2)
= 0.01π

Now, we can rearrange the formula to solve for the thickness of the film:

Thickness of the film = Volume of the drop / Area of the film

Substituting the values:

Thickness of the film = 10^-10 m^3 / (0.01π)

Calculating the numerical value:

Thickness of the film ≈ 10^-10 m^3 / (0.01 × 3.14159)
≈ 10^-10 m^3 / 0.0314159
≈ 3.18 x 10^-9 m

Therefore, the thickness of the film is approximately 3.18 x 10^-9 meters.