At 8: 00 am, the temperature in the earth science room was measured to be 62 degrees fahrenheit. by 12: 00 pm, the temperature had risen to 70 degrees fahrenheit. calculate the rate of change.

Rate of change = (amount of change) / (time for the change)

Amount of change = (temp at the end) minus (temp at the beginning)

Amount of change = (70°F) minus (62°F) = 8°F

Time for the change = (time at the end) minus (time at the beginning)

Time for the change = (1200 - 0800) = 4 hours

Rate of change = (8°F) / (4 hours)

Rate of change = 2°F  per hour

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