Thickness of Film:Constructive Interference @ 547nm, n=1.31

[hardwork]

Homework Statement

Light of wavelength 547nm is incident perpendicularly on a soap film (n=1.31) suspended in air. What is the smallest nonzero film thickness for which reflected light undergoes constructive interference?

Homework Equations

2t = (m + 1/2)(wavelength/nfilm)

The Attempt at a Solution

t = (0+1/2)(547nm/(2*1.31))
t = 104 nm

Is this correct?---------
Could someone please check this as well: https://www.physicsforums.com/showthread.php?t=310439

 

[hardwork]

Anyone?

 

[rl.bhat]

It is correct.