An electric heater is placed inside a room of total wall area 137m^(2) to maintain the temperature inside at 20^(@)C. The outside temperature is -10^(@)C. The walls are made of three composite materials. The inner most layer is made of wood of thickness 2.5 cm the middle layer is of cement of thickness 1 cm and the exterior layer is of thickness 25 cm. Find the power of electric heater assuming that there is no heat losses through the floor annd ceiling. The thermal conductivities of wood, cement and brick are 0.125W//m^(@)C,1.5W//m^(@)C and 1.0W//m^(@)C respectively,

An electric heater is placed inside a room of total wall area 137m^(2)

1.	An electric heater is placed inside a room of total wall area 137m^(2) to maintain the temperature inside at 20^(@)C. The outside temperature is -10^(@)C. The walls are made of three composite materials. The inner most layer is made of wood of thickness 2.5 cm the middle layer is of cement of thickness 1 cm and the exterior layer is of thickness 25 cm. Find the power of electric heater assuming that there is no heat losses through the floor annd ceiling. The thermal conductivities of wood, cement and brick are 0.125W//m^(@)C,1.5W//m^(@)C and 1.0W//m^(@)C respectively,
Answer» 7384 w 1739 w 9000 w 8247 w Answer :C