Four radioactive 10-gram (g) samples with their remaining isotope mass are listed in the table that spans 50 years. Time Americium-241 Californium-249 Silver-108 Mercury-194
10 years 9.84 g 9.80 g 9.84 g 9.85 g
20 years 9.68 g 9.61 g 9.67 g 9.69 g
30 years 9.53 g 9.42 g 9.51 g 9.54 g
40 years 9.38 g 9.24 g 9.36 g 9.39 g
50 years 9.23 g 9.06 g 9.20 g 9.25 g

Which isotope would be expected to have the longest half-life?

A.
Silver-108

B.
Mercury-194

C.
Californium-249

D.
Americium-241

the device is called “ rocket engine”

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