John purchased 13792 kWh of electricity and 2284 CCF of natural gas in a year. The cost of electricity is 6.4 cents/kWh and that of natural gas is 1.7 dollars per CCF. Assuming that 1 CCF of natural gas has 100,000 BTUs and 1 kWh has 3412 BTUs, what is the average cost of 1 MMBTUs for John.

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