Answer:
The decided by staring at and observing the stars.
Explanation:
Answer:
An object which moves in the positive direction has a positive velocity. If the object is slowing down then its acceleration vector is directed in the opposite direction as its motion (in this case, a negative acceleration).
Explanation:
It is because of static electricity
Answer:
100nm-280nm
Explanation:
Ultraviolet rays (UV) are part of the electromagnetic spectrum. It goes from 10nm to 400nm wavelengths, they are shorter than visible light, thus it's impossible to see by a human eye, and larger than X-rays (used in many medical applications and harmful when long-exposed).
According to its wavelengths, UV can be divided in different types:
UVA: long wave UV (315nm-400nm)
UVB: medium-wave UV (280nm-315nm)
UVC: short wave UV (100nm-280nm)
Therefore, UVC comprises wavelengths between 10nm and 280nm.
They are characterized by a regular crystalline organization of atoms that confer a long-range order. Amorphous, or non-crystalline, solids lack this long-range order. Accordingly, they lack the elasticity, distinct melting points, and other properties of crystalline solids