The answer to the problem b.
To develop this problem it is necessary to apply the optical concepts related to the phase difference between two or more materials.
By definition we know that the phase between two light waves that are traveling on different materials (in this case also two) is given by the equation

Where
L = Thickness
n = Index of refraction of each material
Wavelength
Our values are given as





Replacing our values at the previous equation we have




Therefore the thickness of the mica is 6.64μm
1 io is a moon not a planet.
2)C,The Milky Way is a spiral galaxy
3)D,this is called the particle wave duality,stuff can act like particles and waves at the same time.
4)the white dwarfs
5)using distance and compass direction(I’m not sure about this one though)