# Problem: As a soap bubble with n = 1.333 evaporates and thins, reflected colors gradually disappear. What are(a) the bubble thickness just as the last vestige of color vanishes and(b) the last color seen?

###### FREE Expert Solution

The condition for constructive interference for the given condition is:

$\overline{){\mathbf{2}}{\mathbit{\eta }}{\mathbf{d}}{\mathbf{=}}{\mathbf{\left(}}{\mathbf{m}}{\mathbf{+}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbf{\right)}}{\mathbf{\lambda }}}$

m = 0

This implies that:

2ηd = (1/2)λ

d = λ/4η

The minimum bubble thickness that will produce interference color is:

$\overline{){{\mathbf{d}}}_{\mathbf{m}\mathbf{i}\mathbf{n}}{\mathbf{=}}\frac{{\mathbf{\lambda }}_{\mathbf{m}\mathbf{i}\mathbf{n}}}{\mathbf{4}\mathbit{\eta }}}$

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###### Problem Details

As a soap bubble with n = 1.333 evaporates and thins, reflected colors gradually disappear. What are

(a) the bubble thickness just as the last vestige of color vanishes and

(b) the last color seen?