An electric wire having a diameter of 2.3 mm and covered with a plastic insulation of...

An electric wire having a diameter of 2.3 mm and covered with a plastic
insulation of thickness 0.63 mm is exposed to air at 336 K and h= 32W/m2 K. It
is assumed that the wire surface temperature is constant at 415 K and is not
affected by the covering. Calculate the value of the critical radius. Calculate the
heat loss per m of wire length with no insulation and heat loss with insulation
being present.

Data given:

Plastic 0.4 W/mK
brick 0.72W/m°C
plaster 0.36 W/m°C
cement 1.4 W/m°C
Polyurethane foam 0.025W/m °C
Glass fiber/fiber glass 0.036 W/m °C
Air 0.0198 W/m °C
Copper 380W/m °C

# take from the data given just the required

Expert Solution

Amanda K answered 4 months ago

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