Out of red, Blue and yellow lights, the scattering of _______ light is maximum

The sky appears blue due to scattering of light.

Consider the following statements : 1. Clear sky appears blue due to poor scattering of blue wavelength of visible light. 2. Red part of light shows more scattering than blue light in the atmosphere. 3. In the absence of atmosphere, there would be no scattering of light and sky will look black. Which of the statements given above is/are correct?

Whose fringe width will be more, the one for red light or the one for yellow light, all other things be the same ?

Whose fringe width will be larger, the one for red light or the one for yellow light, all other things be the same?

On investigation of light from three different stars A, B and C, it was found that in the spectrum of A, the intensity of red colour is maximum, in B the intensity of blue colour is maximum and in C the intensity of yellow colour is maximum. From these observations, it can be concluded that

Blue light can cause photo electric emission from a metal, but yellow light cannot. If red light Is incident on the metal,