Gravitational force of attraction "f" exists between two-point masses a and b when a fixed distance separates them. after mass a is doubled and mass b is quartered, the gravitational attraction between the two masses

8F

Explanation:

Given

Gravitation attraction is F between A and B

if and is the mass of A and B respectively then

F is given by

where r=distance between them

if is doubled and is quadrupled then Force can be given by

thus force becomes 8 times of initial value

ammonium chloride & tallow

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