Acapacitor stores energy u1 when it holds charge q .the same capacitor stores energy u2 when it holds charge 16 q what is the ratio between u2/u1 the answer is 256 why ?

Ratio between U₂/U₁ = 256

Explanation:

Energy stored in a capacitor is given by

where Q is the charge and C is the capacitance.

We have

and

So,

Ratio between U₂/U₁ = 256

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