A thin film of cooking oil ( n = 1.47 ) is spread on a puddle of water ( n = 1.35 ) . What is the minimum thickness D min of the oil that will strongly reflect blue light having a wavelength in air of 456 nm, at normal incidence?

The minimum thickness of the oil is 77.55 nm

Explanation:

Given:

Refractive index of oil

Refractive index of water

Wavelength of light m

From the equation of thin film interference,

The minimum thickness is given by,

Where , thickness

Here we have to find minimum thickness so we use

    m

    nm

Therefore, the minimum thickness of the oil is 77.55 nm

answer is c

explanation:

the answer would be c