Angles are generally measured counter clockwise from positive x- axis. suppose you have a vector lying in the x-y plane. when you determined its direction using vector method, you got the angle as negative. what does that indicate? both the components of the vector must be negative (lying in the 3rd quadrant). the vector must be lying in the 4th quadrant. 2 at least one of the components of the vector 3 is negative. the vector must be lying in the first quadrant. 4 it is not possible to have a negative angle for a vector. 5 exactly one of the components is negative.

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

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