A building is 6m high, and it is 80m from a converging camera lens. If the camera forms an image which is 6 mm high, (a) What is the magnification? (b) How far must the camera film be behind the lens for the image to be formed?

Explanation:

Two aircrft pand qare flyingatthe same speed 300m the diraction along tothe diraction of the veloctiy

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