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A room at 20^@C is heated by a heater of...

A room at `20^@C` is heated by a heater of resistence 20 ohm connected to 200 VV mains. The temperature is uniform throughout the room and the heati s transmitted through a glass window of area `1m^2` and thickness 0.2 cm. Calculate the temperature outside. Thermal conductivity of glass is `0.2 cal//mC^@` s and mechanical equivalent of heat is `4.2 J//cal`.

A

`15.24^(@)"C"`

B

`15.00^(@)"C"`

C

`24.15^(@)"C"`

D

none of these

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