Question

What is the minimum thickness of a soap bubble needed for constructive interference in reflected light if the light incident on the film has wavelengths 900 nm? Assume the refractive index for the film is n.

Answer 1

To find the minimum thickness of a soap bubble for constructive interference with a 900 nm wavelength light, the formula t = (m + ½)λ/n is used for the first order of interference with m=0. Without the refractive index value n, the exact thickness cannot be provided.

Step-by-step explanation:

The minimum thickness of a soap bubble for constructive interference in reflected light when the light incident on the film has a wavelength of 900 nm can be determined by using the thin film interference formula:

t = (m + ½)λ/n

where t is the film thickness, m is the order of the interference (m=0,1,2,... for constructive interference), λ is the wavelength of light in vacuum, and n is the refractive index of the film. To find the minimum thickness, we use the first order (m=0), so:

t = (0 + ½)900 nm / n = 450 nm / n

In this case, we need the value of the refractive index (n) to calculate the exact minimum thickness. Without it, we can only provide the formula and method to find the thickness.