Question

What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 555 nmnm

Answer 1

The minimum thickness of soap film is
`2.086* 10^(-7) m`.

Step-by-step explanation:

wavelength = 555 nm

refractive index, n = 1.33

For the destructive interference,

the thickness is given by

`t =(m \lambda )/(2 n)`

Here, m is the order, n is the refractive index and
`\lambda` is the wavelength.

For minimum thickness, m = 1

So the thickness is

`t =(1 * 555* 10^(-9) )/(2 * 1.33)\\\\t = 2.086* 10^(-7) m`