MC - Physics

A: This is known as Franunhofer's diffraction. The 1st maximum occurs at an angle approximately equals θ = sin^-1(3λ / 2w), not equal. So, this is wrong.


B: mλ = dsinθ, when slit spacing (d) increases, the corresponding θ will decrease. So, this is correct.


C: mλ = dsinθ, when the same order of grating occurs, for a smaller λ, θ will be smaller too. So, this is correct.


D: The light emitted by the two close stars are unlikely to be at same frequency. So, they are unlikely to be coherent and hence interference pattern cannot be observed. This is wrong.


E: When light travels from a less densed medium and is reflected by a denser medium, it suffers a pi phase change, so the reflected wave is inverted. This is correct.


F: This is the fact. So, this is correct.


G: White light consists of a various of wavelength of light. When the light reflected to be seen, 2d = mλ, so when there is variation of thickness of different parts, different d, the resulting different λ undergoes constructive interference and hence different colors will be seen. This is correct.