The metal iridium has an FCC crystal structure. If the angle of diffraction for
the {220} family of parallel planes occurs at 69.22? (first-order reflection) when
monochromatic x-radiation having a wavelength of 0.1542 nm is used,
compute
(a) the interplanar spacing for this set of planes, and
(b) the atomic radius for an iridium atom

why is arctic sea ice important? arctic sea ice keeps the polar regions cool and moderate global climate. sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. as sea ice melts in the summer, it exposes the dark ocean surface.

let that person have a turn to speak : )

idk what the question is about