A room is maintained at ${20^o}C$ by a heater of resistance $20$ ohm connected to $200$ volt mains. The temperature is uniform through out the room and heat is transmitted through a glass window of area $1{m^2}$ and thickness $0.2$ cm. What will be the temperature outside ....... $^oC$ ? Given that thermal conductivity $K=0.2$ for glass is and $J = 4.2 J/cal$
IIT 1978, Medium
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