How does a positively charged metal ball become neutral

By gaining equal number of electrons to the charge it carries.

Explanation:

A positively charge metal ball will become if it gains equal number of electrons to the charge it carries.

Generally, a body becomes charged when they lose or gain electrons. The loss or gain of electrons by a body is common place feature. Merely rubbing of substances against each other will cause a loss or gain of electrons.

Electrons are negatively charged particles in an atom

Protons are positively charged particles.

In a neutral atom, the number of protons and electrons must be the same.

A positively charge body will have more number of protons than electrons.

To make a positively charged metal become neutral, we bring it to the vicinity of electrons.

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

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