Question

Soap bubbles can display impressive colors, which are the result of the enhanced reflection of light of particular wavelengths from the bubbles' walls. For a soap solution with an index of refraction of 1.29, find the minimum wall thickness that will enhance the reflection of light of wavelength 709 nm in air.

Answer 1

Answer:

The value is  $t = 1.374 *10^{-7} \ m$

Explanation:

From the question we are told that

   The refractive index is  $\mu = 1.29$

    The wavelength is $\lambda = 709 \ nm = 709 *10^{-9} \ m$

Generally the condition for constructive interference is  

          $2 * \mu * t = (n - \frac{1}{2} )\lambda$

At minimum thickness(t)  the order of the fringe(n) will be equal to   1

So

         $2 * 1.29 * t = (1 - \frac{1}{2} )* 709 *10^{-9}$

=>       $t = 1.374 *10^{-7} \ m$