TS EAMCET · Physics · Waves and Sound
Calculate the minimum thickness of a soap film ( \(n=1.33)\) that results in constructive interference in reflected light, if the film is illuminated with light whose wavelength in free space is \(532 \mathrm{~nm}\).
- A \(113 \mathrm{~nm}\)
- B \(100 \mathrm{~nm}\)
- C \(200 \mathrm{~nm}\)
- D \(226 \mathrm{~nm}\)
Answer & Solution
Correct Answer
(B) \(100 \mathrm{~nm}\)
Step-by-step Solution
Detailed explanation
For constructive interference through a thin film in reflected light, thickness of film must be \[ t=\left(m+\frac{1}{2}\right) \frac{\lambda}{2 n_2} \] where, \(m=0,1,2, \ldots\) and \(n_2=\) refractive index of medium (soap film) With given values, we get…
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