What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 535 nm ? The index of refraction of the film is 1.32, and there is air on both sides of the film.

0.203 micro meter

Explanation:

for destructive interference that appearsblack, use the formula

2 t = m λ / u (where m = 0 1 2 3 ... is order of minima)

where t = tickness,

u is the ref index = 1.32

Wavelenth λ = 535×10^-9 meter

for t (minimum) m = 1 (as m=0 is ruled out as t>0)

t = 1× 535×10^-9/2×1.32

t (min) = 202.65×10^-9 meter

OR

t (min) = 0.203×10^-6 meter = 0.203 micro meter

e/c, where e is its total energy

this is an example of "committed" time.

committed time, as contracted time, takes need over essential and available time since it is seen as profitable work. it alludes to the time allotted to keep up a home and family. at the point when a man is commuting using committed time this individual may feel that the drive is an obligation to family, for example, strolling youngsters to class or driving a mate to work. contracted and committed time clients may feel that their commute could really compare to the commute of important or leisure time clients on the grounds that their commute is profitable work. in this manner, they might be more disposed to pick a mechanized method of movement.