Soap bubble interference Light of 690-nm wavelength interferes constructively when reflected from a soap bubble having refractive index 1.33. Determine two possible thicknesses of the soap bubble.

The two possible thicknesses of the soap bubble is 129 nm and 389 nm.

Explanation:

Given that,

Wavelength = 690 nm

Refractive index = 1.33

We need to calculate the two possible thicknesses of the soap bubble

Using formula of thickness

For m = 0,

Put the value into the formula

For m=1,

Put the value into the formula

Hence, The two possible thicknesses of the soap bubble is 129 nm and 389 nm.

what is the actual question though?