8. The figure below shows how to empty water from a large tank into a low
lying container using rubber tubing:
a
B
С
A
2 m
t..
D
(a) Explain why the tube must
be filled with water before the
emptying process starts.
(b) Soon after the tank begins to empty,
the lower end is momentarily
blocked by placing a finger at
end D. Determine the pressure
difference between points A and
D. (Take density of water to be
(1000 kgm )
ri​

explanation:

could i give you a exaplo that could you?

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray