What is the area of the tungsten target called where the high speed electrons strike the surface?

Actual focal spot-

Explanation:

Actual focal spot-

it is referred to that spot of focal where beam of electron converge to one place.

focal sopt size for different process are

1) for mammography - 0.3 mm to 0.6 mm

2) for radiography - 1.00 to 1.2 mm

Focal length of focal spot can be calculated by using following relation

where is angle of anode

south, because if you took a map you would see texas is directly in the middle of east and west, but it is also downwards towards mexico, therefore it is south