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

Q.

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

1. True

2. False