Refraction is caused by any wave crossing the boundary out of one substance and into another one. The two different substances may be no more than two parcels of air at different temperatures.
a) The wind is generated because there are different values of pressure in the amtophera. That is, it is generated due to a pressure difference between two atmospheric points. Generally the movement is performed when the air travels from the highest pressure point, to the lowest pressure point. This is also a direct cause of different types of wind speeds.
b) If the cloud moves from one direction to another, it will indicate that from the starting point the pressure is higher, and the point towards which it is directed, the pressure is lower. If we place this on a Cartesian plane with reference to the cardinal points, we can know the approximate place or area where the pressures are different.
The De Broglie wavelength of the electron is

And we can use De Broglie's relationship to find its momentum:

Given

, with m being the electron mass and v its velocity, we can find the electron's velocity:

This velocity is quite small compared to the speed of light, so the electron is non-relativistic and we can find its kinetic energy by using the non-relativistic formula:
A concussion, which is a form of mild traumatic brain injury, occurs after a blow to the head. The brain is surrounded by fluid and protective membranes called meninges, which usually cushion the brain. During an impact, the brain is pushed against the inside of the skull and can be bruised.