In an Electric Furnace Used for Refining Steel,the Temperature Is

Multiple Choice

In an electric furnace used for refining steel,the temperature is monitored by measuring the radiant power emitted through a small hole in the wall of the furnace,of area 0.5 cm².This hole acts like a perfect blackbody radiator having the same temperature as the interior of the furnace.If the temperature of the furnace (and therefore of the hole) is to be maintained at 1650°C,how much power will the hole radiate?

A) 20 W
B) 30 W
C) 40 W
D) 50 W