Mohammed observed that his water boiled much more quickly than his isopropyl alcohol. His peer group suggested some experimental errors that
may have caused this to happen. Which two experimental errors most likely
caused the invalid data?
A. Mohammed's procedure was correct, but he tested a type of
water that boils more quickly than isopropyl alcohol.
B. The heating vessel or hot plate was not at the same temperature
each time.
C. The boiling vessel might have been dirty, so the solutions got
mixed.
D. Mohammed could have mixed up the labels on the containers.

double the distance = divide strength by 4

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