Water is boiled in a 1-l coffee maker with an immersion-type electric heating element at atmospheric pressure. it was observed that ½-l has evaporated in 13 min once boiling starts. a) if the heating element is rated based on power required to evaporate water, determine the rating of the heating element. b) for the same heating element, how long will it take to raise the 1-l temperature from 18 oc to boiling point at the same atmospheric pressure? take liquid water density air = 1000 kg/m3 & specific heat cpwater = 4.18 kj/(kg. ok).

as technology advances, new experiments often expose problems in accepted theories. c

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-lavira: )

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

drying towels at the beach