Athin film soap bubble (n=1.35) is floating in air. if the thickness of the bubble wall is 300nm, which of the following wavelengths of visible light is strongly reflected?

540 nm

Explanation:

According to the question,

The refractive index of the soap bubble, .

The thickness of the soap bubble wall is, .

Now, for constructive interference of soap bubble.

.

Now for first order m=1.

Therfore,

Substitute all the variables in the above equation.

.

Therefore,

.

Therefore the visible light wavelength which is strongly reflected is 540 nm.

the right answer is 0.3 meters per second