Maxima in Diffraction

Q. What is the minimum thickness of a soap film needed for constructive interference in reflected light, if the light incident on film is of wavelength $900\text{nm}$ ?
Refractive index of film is $1.5$.

1. $100\text{nm}$
2. $150\text{nm}$
3. $200\text{nm}$
4. $250\text{nm}$

Q. What is the minimum thickness of a soap film needed for constructive interference in reflected light, if the light incident on film is of wavelength $900\text{nm}$ ?
Refractive index of film is $1.5$.

1. $100\text{nm}$
2. $150\text{nm}$
3. $200\text{nm}$
4. $250\text{nm}$

Q.

The bright spots (except the central one), we just found the position of, are maxima.

1. True

2. False