<u>Answer:</u> The spacing between the crystal planes is 
<u>Explanation:</u>
To calculate the spacing between the crystal planes, we use the equation given by Bragg, which is:

where,
n = order of diffraction = 2
= wavelength of the light =
(Conversion factor:
)
d = spacing between the crystal planes = ?
= angle of diffraction = 22.20°
Putting values in above equation, we get:

Hence, the spacing between the crystal planes is 
Magnesium and I think its MG12 for the other part
Hey <span>wademcelroy2005, thanks for submitting your question to Brainly!
The answer to your question is </span><span>B:Radiation moves from a warmer object to a cooler object</span>
It shows the type of atoms/elements in a substance
Different types of atoms have different emission spectrum - a concept supported by Bohr quantum theory - hence one is able to identify elements in a substance using a method called spectroscopy.
Explanation:
When an electron jumps from a low energy orbital to a higher energy orbital in an atom, it absorbs a specific wavelength of electromagnetic radiation (This is called absorption spectrum). Vice versa, if the same electron jumps from a higher to a lower energy orbital it releases the equivalent quantum energy in electromagnetic wave (This is called emission spectrum). Different types of atoms of different elements have a unique spectrum identifier.
Learn More:
Learn more about spectroscopy;
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