Aspartic acid is a polypeptide side chain found in proteins. The pKa of aspartic acid is 3.86. If this polypeptide were in an aqueous solution with a pH of 7, the side chain would have what charge? a) negative b) positive c) neutral d) there is no way to know

a) Negative

Explanation: According to the question: The pKa of aspartic acid is 3.86.

For acidic amino acids,

pH > pKa 

When side chains are negatively charged, amino acid will be acidic

pH < pKa 

That is, when side chains are uncharged, amino acid will be neutral

For aspartic acid, when this polypeptide were in an aqueous solution with a pH of 7

pH (7.0)  > pKa (3.86)

Therefore the chains are negatively charged

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