If aluminum is diffused into a thick slice of silicon with no previous aluminum in it at a temperature of 1100°c for 6 h, what is the depth below the surface at which the concentration is 1016 atoms/cm3 if the surface concentration is 1018 atoms/cm3? d = 2  10-12 cm2 /s for aluminum diffusing in silicon at 1100°c.

since you're a real machine, your ama is always less than your ima, because you can never totally eliminate friction.

mass and volume are the answers you are looking for

the aurora is formed when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. these collisions result in countless little bursts of light, called photons, which make up the aurora.

auroras are generated by charged solar particles hitting molecules in earth's atmosphere. this usually happens in high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles. that’s why it can be experienced in northern ohio.

365.25 earth days are in the year of a light year