A balanced wye-connected three-phase source has line-ta-neutral voltages of 440 V rms. Find the rms line-ta-line voltage nlagnitude. If this source is applied to a wye-connected load composed of three 30-!1 resistances~ find the rms line-current magnitude and the total power delivered

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.