The sideview mirrors on cars are convex mirrors. Let's say the mirror on the driver's side of your car has a focal length with a magnitude of 6.90 m and a truck is at a distance of 4.00 m from the mirror. The truck is the object for the convex sideview mirror. Determine the following:

a. Image distance of the truck (Include the appropriate positive or negative sign.)
b. Magnification for this object distance (Include the appropriate positive or negative sign.)

a)  i = -2.53 m , b)  m = 0.63

Explanation:

a) For this exercise we use the constructor equation

     1 / f = 1 / o + 1 / i

Where f is the focal length, o the distance to the object and i the distance to the image

In this exercise they give the focal length f = -6.90 m, the negative sign is a convex mirror, and the distance to the object is o = 4.00 m

 Let's find the distance to the image

         1 / i = 1 / f - 1 / o

         1 / i = 1 / -6.90 - 1/4

          1 / i = -0.1449-0.25 = 0.3949

          i = -2.53 m

.b) the expression for the magnification is

          m = - i / o

          m = - (-2.53) / 4

          m = 0.63

i think the answer would be reserve.

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